Process for producing sterile suspensions of slightly soluble basic peptide complexes, sterile suspensions of slightly soluble basic peptide complexes, pharmaceutical formulations containing them, and the use thereof as medicaments

ABSTRACT

The present invention provides a novel process for producing sterile suspensions of slightly soluble basic peptide complexes. The present invention further provides a novel process for producing sterile lyophilizates of slightly soluble basic peptide complexes. In addition, a novel process for producing sterile suspensions suitable for the parenteral administration of slightly soluble basic peptide complexes is provided. The invention moreover provides sterile suspensions and sterile lyophilizates of slightly soluble basic peptide complexes, and pharmaceutical formulations comprising them. The provided sterile suspensions, sterile lyophilizates and pharmaceutical formulations comprising them are particularly suitable for use in a parenteral dosage form as medicaments for the treatment and prophylaxis of diseases and pathological states in mammals, especially in humans.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional application60/637,770 filed Dec. 22, 2004, and 60/______ (Attorney Docket 282407US)filed Dec. 5, 2005, both incorporated herein by reference.

TECHNICAL FIELD

The invention relates to a novel process for producing sterilesuspensions and sterile lyophilizates of slightly soluble basic peptidecomplexes. The invention further relates to sterile suspensions andsterile lyophilizates, and to pharmaceutical formulations which compriseone or more lyophilizates, preferably produced according to theinvention, of slightly soluble basic peptide complexes. The suspensionsand lyophilizates produced according to the invention can be used asmedicaments for example for the treatment of benign or malignantneoplastic diseases, in hormone therapy, for the treatment of fertilitydisorders and for contraception, for the treatment of HIV infections andfor the treatment of neurological or neurodegenerative disorders.

BACKGROUND OF THE INVENTION

Sufficiently high bioavailability and, as a consequence, therapeuticefficacy of peptides is frequently ensured only by parenteraladministration, because peptides undergo proteolytic degradation afteroral administration, only low absorption takes place nasally, and noabsorption takes place dermally. Because of the low half-life ofpeptides in the body, parenteral administration of peptide medicaments,e.g. luteinizing hormone releasing hormone (LHRH) analogs such as theso-called superagonists, for example goserelin (INN), leuprorelin (INN)or triptorelin (INN), and LHRH antagonists such as, for example, antide(INN), cetrorelix (INN), degarelix (INN) or ganirelix (INN), must takeplace each day within a therapy period in order to achieve and maintainthe desired suppressant effects on luteinizing hormone (LH) andfollicle-stimulating hormone (FSH).

The result of this suppression in men is the reduction in the productionand release of testosterone and in women there is a reduction in theproduction and release of estradiol, it being perfectly possible for thedegree of reduction required to vary between the medical indications.Lowering the blood levels of sex hormones is a standard therapy in thepalliative treatment of sex hormone-sensitive tumors, for which apermanent reduction to a low level (castration) is necessary. It is alsostandard therapy for the treatment of benign gynecological or urologicaldisorders, e.g. endometriosis, uterine leiomyomas, uterine fibroids andbenign prostate hyperplasia (BPH), for the treatment of fertilityimpairments and for contraception, it also being possible in thesecases, depending on the therapeutic strategy, for intermittent partialreduction of the sex hormone levels to be sufficient.

The need for depot formulations which can be administered parenterallyfor long-lasting and controlled release of peptide medicaments, makingthe need for daily administrations obsolete, was recognised a relativelylong time ago.

DE 38 22 459 A1 discloses pharmaceutical formulations which comprisecomplexes of water-insoluble peptides, such as, for example, LHRHanalogs, with embonic, tannic and stearic acid and biodegradable lacticacid-glycol acid copolymers. In the production process disclosedtherein, chlorinated hydrocarbons such as dichloromethane are employedas solvents and subsequently removed for the most part by rotaryevaporation. However, the use of such potentially carcinogenic solventsis disadvantageous because of the high residual solvent content, e.g.−4500 ppm dichloromethane (Koushik K and Kompella UB, PharmaceuticalResearch, 2004, 21: 524-535), in pharmaceutical forms produced bysolvent evaporation. The ICH guideline “Impurities: Guideline forResidual Solvents—Q3C” strictly limits the residual solvent content forclass 2 solvents in pharmaceutical products for reasons of drug safety,e.g. for the chlorinated hydrocarbons dichloromethane and chloroform torespectively 600 ppm and as low as 60 ppm. A further crucialdisadvantage is the rotary evaporation of the volatile toxic solventbecause of the risk of contamination and explosion. Use of chlorinatedhydrocarbons in the production process additionally represents a hazardfor employees and the environment. Sterility of the pharmaceuticalformulations is achieved only by a subsequent gamma irradiation. Besidesthe aspects of considerable additional costs and increased potentialhazards for employees and the environment, subsequent gamma irradiationalso leads however, because of the higher radiation dose (25 kGyaccording to Ph. Eur.), to increased decomposition and therefore has adisadvantageous effect on the stability of such formulations. Inaddition, the use of gamma irradiation represents a particular obstacleto authorization with elaborate qualification and validationrequirements (see: EC Guide to Good Manufacturing Practice—Annex 12).

U.S. Pat. No. 5,134,122 describes the production of microparticles of alactic acid-glycolic acid copolymer which comprise, as pharmaceuticallyactive substance, peptides in the form of their water-insolubleembonate, tannate, stearate or palmitate salts. However, the processdescribed therein requires the disadvantageous use of special elaborateextrusion machines and a thermal treatment at up to 100° C., which maylead to destruction of the peptides and to a greater level ofcontamination of the pharmaceutical form by increased degradation orcondensation products. A further disadvantage of the process is the needto sieve the microparticles in order to obtain the desired particlesize. Such a sieving step is scarcely possible in an aseptic productionprocess in a clean room because of the potential particle contamination(see: EC Guide to good Manufacturing Practice—Annex 1).

DE 42 23 282 A1 and DE 42 23 284 A1 (and U.S. Pat. No. 5,445,832 andU.S. Pat. No. 5,637,568 as US patents belonging to the patent family)describe processes for producing pharmaceutical preparations in whichwater-insoluble medicamentous peptide substances are incorporated intomicroparticles of a biodegradable polymeric material. Both processeshave the already described disadvantage of the obligatory use ofcarcinogenic chlorinated hydrocarbons and the problem of physiologicallyunacceptable residual solvent contents. A further disadvantage is thelow percentage loading of the microparticles with active ingredient, andthe already discussed gamma irradiation.

DE 43 42 092 A1 (and U.S. Pat. No. 5,773,032 as US patent belonging tothe patent family) discloses the nonsterile production of slightlysoluble salts of peptide LHRH analogs by reacting an aqueous solution ofthe acid salt with an acetic acid solution of the LHRH analog base toprecipitate the slightly soluble acid addition salt, and the use thereofas medicaments. One disadvantage of this process is, however, theobligatory filtration step which, on the pilot and production scale, onuse of, for example, 30 g of peptide in the batch, leads to theformation of inhomogeneous gelatinous peptide precipitates which cannotbe resuspended and cause intolerable long filtration times. In addition,the filtration is associated with a disadvantageous coprecipitation ofalkaline earth metal and alkali metal salts, such as, for example,sodium acetate, which may promote decomposition of the peptide salt, andmay lead to tolerability problems occurring in patients on parenteraladministration. Further disadvantages of this production process are theuse of organic solvents such as dimethylacetamide and dimethyl acetate,with the already described problem of the residual solvent content, andthe necessary sieving step which is scarcely possible, as alreadymentioned above, on aseptic production in a clean room. In addition, thesalts and suspensions described in DE 43 42 092 A1 and produced by thedisclosed process are not sterile, because the process described thereinand including the process steps of ‘filtration’ and ‘drying’ cannotindustrially result in intrinsically sterile process products (there:dried filter cake as precipitate), thus making for example directparenteral administration, but also further processing in an asepticprocess, impossible.

The lacking sterility, which is an obligatory requirement for asepticfurther processing and administration of such salts and suspensions asmedicaments, could be achieved only by an additional sterilization step,which is not disclosed in DE 43 42 092 A1, by gamma irradiation.

As already discussed above, however, subsequent gamma irradiation leads,because of the high radiation dose, to an increased decomposition andtherefore has disadvantageous effects on the stability of such salts andsuspensions, besides the aspects of considerable additional costs,increased potential hazards for employees and the environment andelaborate qualification and validation measures. In addition, the saltsproduced according to DE 43 42 092 A1 are in the form of microparticleswith which it is not possible to generate suspensions which are stablefor a prolonged period without, or even with, addition of additiveswhich increase the viscosity and assist resuspendability. Although it ispossible to generate a suspension, e.g. in aqueous solution, withcontinuous mixing, it corresponds rather to an agitation of the solidmicroparticles in the liquid phase. If the mixing is stopped orinterrupted, a two-phase mixture quickly forms again and consists ofsolid phase (microparticles) and liquid phase (aqueous solution)separate from one another.

Felberbaum et al. (Human Reproduction, 1998, 13: 1660-1668) describe theuse of the cetrorelix embonate microparticles produced according to DE43 42 092 A1 in the treatment of uterine fibromas. A sterile suspensionof the microparticles treated by gamma irradiation, in which themicroparticles were resuspended in an aqueous solution with the additionof polysorbate 80, sodium hydroxide solution and carboxymethylcellulose(CMC), was employed. However, as already indicated above, such aformulation of cetrorelix embonate microparticles does not represent asuspension which is stable for a prolonged period even with addition ofadditives which increase the viscosity and assist resuspendability; onthe contrary it quickly separates again to a two-phase mixture composedof liquid and solid phase separate from one another.

Additionally, however, the addition of viscosity-increasing CMCrepresents a considerable disadvantage because CMC may lead, especiallyon parenteral administration, to allergic reactions or even anaphylaxis(Bigliardi et al., Dermatology 2003, 207:100-103; Oppliger and Hauser,JDDG 2004, 2:928-930), and should therefore be avoided. Furthermore,administration of the microparticle suspension led to inadequateestradiol suppression in some patients. On the other hand, in otherpatients there was a reduction in the estradiol level to distinctlybelow 20 pg/ml and thus an unwanted chemical castration (see also:Kaufmann et al., Journal of Clinical Oncology 1989, 7: 1113-1119;Battaglia et al., Gynecological Endocrinology 1995, 9: 143-148; Reron etal., Neuroendocrinology Letters 2002, 23: 455-458) with thecorresponding hormone withdrawal manifestations which aredisadvantageous for the patients. The authors themselves speak of theneed for an improved formulation which avoids the observeddisadvantages.

DE 100 40 700 A1 (and U.S. Pat. No. 6,780,972, US 2002/198146 and US2004/259801 as US patents belonging to the patent family) describes aprocess for producing slightly soluble peptide salts, in which thedissolved initial peptide salt of a basic peptide is reacted with amixed bed ion exchanger or a mixture of an acidic and basic ionexchanger to form the free basic peptide, subsequently the ion exchangeris removed, the free basic peptide is reacted with an acid to form thefinal peptide salt, and finally the solvent is removed. The processdisclosed therein has the disadvantage, however, that nonsterile ionexchangers not complying with GMP guidelines must be used and represent,because of organic residues such as sulfonic acid residues andmicrobiological residues, a potential source of contamination. Thus, themicrobiological load of the inner cavities of the nonsterile ionexchanger particles cannot be ascertained straightforwardly before use.The use of such ion exchangers represents an unacceptable andunpredictable risk of contamination of the peptide complexes to beprepared because of possible mechanical damage or possible destructionof the particles during the reaction process, such as, for example, bystirring or shaking. A further disadvantage is the instability of thefree peptide base in basic solution, which leads to increaseddecomposition products in only a short time, e.g. after only 10 minutes,which would according to the ICH guideline “Impurities in New DrugProducts—Q3B(R)” make elaborate identification and qualificationmeasures necessary for the suspensions disclosed in the patent. Thisdisadvantageous decomposition can only partly be counteracted by a largemolar excess of ion exchanger, which in turn entails the disadvantage oflower product yields (approx. 15-20% loss of yield) in the reaction. Afurther disadvantage of the disclosed process is the increased thermalstress on the slightly soluble peptide salts due to the need to removethe solvent by distillation, which likewise leads to increaseddecomposition products and thus a greater degree of contamination in thepharmaceutical form. In addition, removal of volatile solvents bydistillation is scarcely possible in a clean room area because of therisk of contamination and explosion. Moreover, the suspensions producedby the disclosed process are not necessarily sterile and may even, forthe reasons mentioned above, be microbiologically contaminated. Withsparingly soluble peptide salts prepared by the process of DE 100 40 700A1 there is accordingly always a need before use for parenteraladministration that they be sterilized, for example by gammairradiation, which is associated with the disadvantages alreadydescribed.

DESCRIPTION OF THE INVENTION

The present invention therefore has the object of providing a novelprocess which makes it possible to produce sterile suspensions andsterile lyophilizates of slightly soluble basic peptide complexes andmoreover to avoid the disadvantages, described above, of the knownprocesses, such as gamma sterilization, the use of toxic organicsolvents, the generation of peptide salt particles which are difficultto resuspend etc. A further object of the invention is the provision ofsterile suspensions of such slightly soluble basic peptide complexes,which can be directly administered parenterally or directly processedfurther in an aseptic production process, e.g. by lyophilization, andthe provision of corresponding sterile lyophilizates of such slightlysoluble basic peptide complexes.

The object of the invention has been achieved in one aspect in asurprising manner by providing a novel process for producing sterilesuspensions of slightly soluble basic peptide complexes, that comprises,under aseptic conditions,

-   a) i) mixing a sterile solution comprising    -   a salt or a complex of a basic peptide and    -   an aliphatic or aromatic organic carboxylic acid and/or salts        thereof    -    in a solvent or solvent mixture, optionally with the addition        of solubility-increasing and/or agglomeration-suppressing        additives, or    -   ii) combining and mixing a sterile solution of a salt or complex        of a basic peptide in a solvent or solvent mixture and a sterile        solution of an aliphatic or aromatic organic carboxylic acid        and/or salts thereof in a solvent or solvent mixture, optionally        with the addition of solubility-increasing and/or        agglomeration-suppressing additives,-   b) generating, by mixing and addition of a diluent or diluent    mixture in one or more steps, a suspension of a slightly soluble    basic peptide complex of the basic peptide with the carboxylic acid,    which complex precipitates at the latest after addition of the    diluent or diluent mixture,-   c) depleting, while mixing in a continuous or stepwise separation    process, the solvent or solvent mixture, the free non-peptide ions,    the excess carboxylic acid and the optionally added    solubility-increasing and/or agglomeration-suppressing additives in    the resulting suspension, with the liquid content of the suspension    being reduced and optionally further diluent or diluent mixture    being added in one or more steps, and-   d) adding, while mixing the sterile suspension thus obtained, the    slightly soluble basic peptide complex, optionally pharmaceutical    excipients, carriers and/or bulking agents.

In a preferred embodiment, the above-described process for producingsterile suspensions of slightly soluble basic peptide complex comprisesthe sterile solution of the salt or complex of the basic peptide and thesterile solution of the aliphatic or aromatic organic carboxylic acidand/or salts thereof being present in the same solvent or solventmixture in step a) ii).

In a further aspect, the object of the invention has surprisingly beenachieved by providing a novel process for producing sterilelyophilizates of slightly soluble basic peptide complexes, thatcomprises lyophilizing the sterile suspension of the slightly solublebasic peptide complex which has been obtained in steps c) or d) of theprocess just described for producing sterile suspensions of slightlysoluble basic peptide complexes, and optionally adding pharmaceuticalexcipients, carriers and/or bulking agents to the lyophilizate obtained.

In a further aspect, the object of the invention has surprisingly beenachieved by providing a novel process for producing sterile suspensions,suitable for parenteral administration, of slightly soluble basicpeptide complexes, which comprises reconstituting the lyophilizate ofthe slightly soluble basic peptide complex which has been obtained bythe process just described for producing sterile lyophilizates ofslightly soluble basic peptide complexes with a sterile physiologicallytolerated reconstituting medium.

In a further aspect, the object of the invention has surprisingly beenachieved by providing sterile suspensions of a slightly soluble basicpeptide complex obtainable by the process just described for producingsterile suspensions of slightly soluble basic peptide complexes andprocesses for producing sterile suspensions, suitable for parenteraladministration, of slightly soluble basic peptide complexes.

In a further aspect, the object of the invention has surprisingly beenachieved by providing sterile lyophilizates of a slightly soluble basicpeptide complex obtainable by the process just described for producingsterile lyophilizates of slightly soluble basic peptide complexes.

The term “basic peptide” means for the purposes of this inventionpeptides consisting of 2-50 naturally occurring and/or synthetic aminoacids, preferably 5-20 amino acids, particularly preferably 9-10 aminoacids, which comprise one or more basic amino acids such as, forexample, arginine, histidine, pyridylalanine or lysine, and/or at leastone basic group, for example a primary, secondary or tertiary aminogroup, such as, for example, the groups “—NH₂”, “—NHR” or “—NR₂”, whereR is selected from the group consisting of “alkyl, alkyloxy, aryl,heteroaryl, aralkyl, heteroaralkyl, aralkyloxy, heteroaralkyloxy” (asdescribed in U.S. Pat. No. 5,942,493) and have overall a basiccharacter.

Preferred basic peptides are LHRH analogs, and those particularlypreferred are the so-called LHRH super-agonists goserelin, leuprorelin,triptorelin and the LHRH antagonists antide, A-75998, cetrorelix,ozarelix [D-63153,Ac-D-Nal(2)-4-Cl-D-Phe-D-Pal(3)-Ser-N-Me-Tyr-D-HCi-Nle-Arg-Pro-D-Ala-NH₂;where Nal(2) means 2-naphthylalanine, Pal(3) means 3-pyridylalanine, Memeans methyl, HCi means homocitrulline and Nle means norleucine],degarelix, ganirelix, NaI-Glu antagonist, teverelix (Antarelix®), andthe antagonists according to the compounds: the compounds disclosed inthe patent application U.S. Pat. No. 5,942,493, of the general formula(I)

in which n is the number 3 or 4, R1 is an alkyl group, an alkoxy group,an aryl group, a heteroaryl group, an aralkyl group, a heteroaralkylgroup, an aralkyloxy group or a heteroaralkyloxy group, in each caseunsubstituted or substituted, R2 and R3 are independently of one anothereach a hydrogen atom, an alkyl group, an aralkyl group or aheteroaralkyl group, in each case unsubstituted or substituted, wherethe substitution in turn may consist of an aryl group or heteroarylgroup, or —NR²R³ is an amino acid group, and R4 is a group having theformula (II)

in which p is an integer from 1 to 4, R5 is hydrogen or an alkyl groupand R6 is an unsubstituted or substituted aryl group or heteroarylgroup, or R4 is a ring of the general formula (III)

in which q is the number 1 or 2, R7 is a hydrogen atom or an alkylgroup, R8 is a hydrogen atom or an alkyl group and X is an oxygen orsulfur atom, where the aromatic or heteroaromatic radicals may be partlyor completely hydrogenated and chiral carbon atoms may have the R or Sconfiguration,the LHRH antagonists according to the compounds of the general formula(IV)Ac-D-Nal(2)-D-(pCl)Phe-D-Pal(3)-Ser-Tyr-D-Xxx-Leu-Arg-Pro-D-Ala-NH₂  (IV)in which D-Xxx is an amino acid group of the general formula (V)

in which n is the number 3 or 4, R4 is a group having the formula (VI)

in which p is an integer from 1 to 4, R5 is hydrogen or an alkyl groupand R6 is an unsubstituted or substituted aryl group or heteroarylgroup, or R4 is a ring of the general formula (VII)

in which q is the number 1 or 2, R7 is a hydrogen atom or an alkylgroup, R8 is a hydrogen atom or an alkyl group and X is an oxygen orsulfur atom, andthe LHRH antagonists according to the compounds of the following generalformula (VIII)A-Xxx¹-Xxx²-Xxx³-Xxx⁴-Xxx⁵-Xxx⁶-Xxx⁷-Xxx⁸-Xxx-⁹-Xxx¹⁰-NH₂  (VIII)in whichA is an acetyl or a 3-(4-fluorophenyl)propionyl group,Xxx¹ is D-Nal(1) or D-Nal(2),Xxx²-Xxx³ is D-Cpa-D-Pal(3) or a single bond,Xxx⁴ is Ser,Xxx⁵ is N-Me-Tyr,Xxx⁶ is D-Cit, D-Hci or a D-amino acid group of the general formula (IX)

in which n is the number 3 or 4, where R1 is a group having the generalformula (X)—(CH₂)_(p)—CO—NR2R3  (X)in which p is an integer from 1 to 4, R2 is hydrogen or an alkyl groupand R3 is an unsubstituted or substituted aryl group or heteroarylgroup, and R1 is a 3-amino-1,2,4-triazole-5-carbonyl group or R1 is aring of the general formula (XI)

in which q is the number 1 or 2, R4 is a hydrogen atom or an alkylgroup, R5 is a hydrogen atom or an alkyl group and X is an oxygen orsulfur atom,Xxx⁷ is Leu or Nle,Xxx⁸ is Arg or Lys(IPr),Xxx⁹ is Pro andXxx¹⁰ is Ala or Sar.

Further peptides are abarelix, azaline B, detirelix, ramorelix andRS-68439. The structures of said peptides are to be found inter alia in:Behre et al., GnRH antagonists: an overview, Proceedings of the 2ndWorld Conference on Ovulation Induction, The Parthenon Publishing GroupLtd.; Kutscher et al., Angew. Chem. 1997, 109, 2240; Stoeckemann andSandow, J. Cancer Res. Clin. Oncol. 1993, 119, 457.

The LHRH antagonists particularly preferred for the purposes of thepresent invention are cetrorelix, ozarelix (D-63153) and teverelix(Antarelix®).

The terms “basic character” and “basic” relating to basic peptide meansfor the purposes of this invention that the pure peptide, i.e. the purepeptide base without salt adducts and/or other additions, has a pHgreater than 7.00 as saturated solution in water under standardconditions.

Standard conditions mean the temperature of about 22° C. known to theskilled worker, and the atmospheric pressure of about 1000 hPa (10⁵ Pa),with normal variations such as, for example, weather- and season-relatedchanges also to be taken into account.

The starting material employed in the process of the present inventionin step a) is normally not the free base of the basic peptide, owing toits lack of stability and solubility, but a salt or a complex of thebasic peptide. This salt employed as starting material or this complexemployed as starting material is usually a salt which is soluble in asuitable solvent or solvent mixture, or a soluble complex. Solvents orsolvent mixtures suitable for the purposes of the present invention aredetailed below.

In a preferred embodiment, the salt employed in step a) or the complexof the basic peptide in the process according to the invention is a saltwhich is not slightly soluble or a complex which is not slightlysoluble, preferably a salt or complex selected from the group consistingof: “acetate, hydrochloride, chloride, fluoride, bromide, iodide,gluconate, glucuronate, trifluoroacetate, glutamate, lactate, phosphate,hydrogen phosphate, dihydrogen phosphate, aspartate, succinate,tartrate”.

The term “basic peptide complex” includes according to the invention thecombination of two or more components to form a system which need not besubject to any definite stoichiometry and in which at least onecomponent is a basic peptide and at least one component is an aliphaticor aromatic organic carboxylic acid, where the combination of thecomponents is caused by a superimposition of interactions involvingmainly secondary valence linkages but also ionic interactions.

Thus, the molar ratio of basic peptide to carboxylic acid in the basicpeptide complex may assume for example all values between 100:1 and1:100, preferably between 20:1 and 1:20, more preferably between 5:1 and1:5 and particularly preferably between 2:1 and 1:2.

The basic peptide complex need not, in contrast to the basic peptide,itself have any basic character or be basic. It may for example alsohave a pH of less than or equal to 7.00.

The slightly soluble peptide complex of the basic peptide with thecarboxylic acid which is generated in step b) of the process describedabove results from reaction of the starting materials dissolved in theone sterile solution after step a) i) or the two sterile solutions afterstep a) ii) of the process and differs from the salt or complex,dissolved therein, of a basic peptide. This reaction is normally achemical reaction, for example a conventional metathesis, whoseequilibrium can be shifted for example because of the slight solubilityin the direction of the resulting and precipitating basic peptidecomplex.

The starting materials, i.e. the salt or the complex of a basic peptideand the aliphatic or aromatic organic carboxylic acid and/or saltsthereof can, before carrying out step a) of the process described above,or for its preparation, optionally be dissolved together [as in step a)i)] or separately from one another [as in step a) ii)] in the same ordifferent solvents or solvent mixtures and be sterilized. If thesolutions are prone to premature precipitation on mixing or if prematureformation of a suspension occurs, and therefore sterilizing filtrationcan no longer be carried out, preference is to be given to step a)according to variant a) ii).

In a further preferred embodiment, the processes according to theinvention comprise a sterile solution comprising a salt or complex of abasic peptide and an aliphatic or aromatic organic carboxylic acidand/or salts thereof in a solvent or solvent mixture being mixed in stepa), optionally with the addition of solubility-increasing and/oragglomeration-suppressing additives.

In a further preferred embodiment, the processes according to theinvention comprise preparing the sterile solution for step a) by

-   a) dissolving a salt or complex of a basic peptide in a solvent or    solvent mixture,-   b) adding the aliphatic or aromatic organic carboxylic acid and/or    salts thereof in solid, suspended or dissolved form with mixing to    the solution of the salt or complex of a basic peptide from step a),    and dissolving, and-   c) sterilizing the solution obtained in this way by filtration.

The sterilization of the solution or solutions in step a) generallytakes place preferably by sterilizing filtration, sterilization byradioactivity such as, for example, gamma irradiation not beingappropriate.

The slightly soluble peptide complex, which has been generated in stepb) of the processes according to the invention, and precipitates at thelatest after addition of the diluent or diluent mixture, of the basicpeptide with the carboxylic acid may also be slightly soluble within themeaning of this invention in the original solvent or solvent mixture,and/or precipitates to form a suspension, even before addition of thediluent or diluent mixture.

The term “slightly soluble” relating to “basic peptide complex” meansfor the purposes of this invention that the solubility, i.e. the maximumamount of the salt or complex of the basic peptide which dissolves in asolvent and/or diluent or mixtures thereof under standard conditions, isequal to or less than 1000 mg/l, preferably 300 mg/l, particularlypreferably 100 mg/l. The solvent or diluent or mixtures thereof employedto determine the solubility is preferably a solvent and/or diluent ormixtures thereof used for the purposes of this invention, preferablywater.

Assessment and assignment of the criterion “slightly soluble” inrelation to “basic peptide complex” for the purposes of this inventionare decided by the solubility of the basic peptide complex aftercomplete addition of the diluent or diluent mixture in step b) andbefore carrying out step c) of the process described above in themixture, which is then present, of solvent and diluent or mixturesthereof, irrespective of whether an addition of the diluent or diluentmixture takes place in one or more steps. The solubility can easily beestablished by the skilled worker on the basis of his expert knowledge,e.g. by appropriate preliminary tests.

In a preferred embodiment, the processes according to the inventioncomprise further diluent or diluent mixture being added in one or more,preferably in more, steps with mixing in the separation process in stepc).

In a further preferred embodiment, the processes according to theinvention comprise employing the same diluent or diluent mixture in stepb) and in step c).

Suitable as carboxylic acid according to the invention are branched orunbranched, saturated or unsaturated aliphatic organic carboxylic acidsand aromatic organic carboxylic acids consisting of from 2 to 30 carbonatoms, it being possible for the latter to consist of one or morearomatic ring systems, to be fused or non-fused, to be substituted ornot substituted on the aromatic ring system. Such carboxylic acids mayalso be polycarboxylic acids, for example di-, tri- or tetra-carboxylicacids, or else sulfonic acids or phosphoric acids. Preferred for a useaccording to the invention is pharmaceutical and toxicologicalacceptability as known to the skilled worker, for example from the GRAS(“General Recognized As Safe”) list. Additionally preferred for thepurposes of this invention are adipic acid, alginic acid, malic aid,ascorbic acid, benzene-sulfonic acid, succinic acid, dibutyl phosphoricacid, dihexadecyl phosphoric acid, dioctyl phosphoric acid, acetic acid,fumaric acid, gluconic acid, glucuronic acid, glutamic acid,alpha-lipoic acid, maleic acid, malonic acid, lactic acid, octylphosphoric acid, oleic acid, tartaric acid and/or salts thereof, suchas, for example, ammonium salts and salts of the alkali metals andalkaline earth metals. Particularly preferred for the purposes of thisinvention are embonic acid, citric acid, palmitic acid, salicylic acid,tannic acid, stearic acid, benzoic acid, cinnamic acid and/or saltsthereof, such as, for example, ammonium salts and salts of the alkalimetals and alkaline earth metals.

In a further preferred embodiment, the aliphatic or aromatic organiccarboxylic acids are selected from the group consisting of “embonicacid, citric acid, palmitic acid”.

Examples of suitable solvents and/or diluents are: water, ethanol,acetic acid, methanol, propanol, iso-propanol, n-butanol, tert-butanol,acetone, or methyl ethyl ketone or a mixture of two or more of theabovementioned solvents as solvent mixture and/or diluent mixture.Solvents and diluents may be identical or different. Preferred solventsor solvent mixtures are water, ethanol, acetic acid, isopropanol,tert-butanol or acetone and mixtures thereof. Aqueous solvent mixtures,i.e. mixtures of one or more organic solvents, such as, for example,those listed above, and water with a water content of 1-90%, preferably4-80%, are particularly preferred.

It is particularly preferred to employ as solvent mixture awater-ethanol mixture having an ethanol content of from 10 to 99% (m/m),preferably 20 to 96% (m/m), with preference 50 to 90% (m/m), inparticular around 70% (m/m).

Preferred diluents are water, ethanol, acetic acid, methanol, propanol,isopropanol, n-butanol, tert-butanol, acetone or methyl ethyl ketone ormixtures of two or more of these diluents.

The particularly preferred diluent is water.

In one variant, the additives which increase the solubility and/orsuppress agglomeration, in particular gel formation, and which areoptionally to be added in step a) of the process for producing sterilesuspensions of slightly soluble basic peptide complexes are added duringthe production of the joint solution or of the separate solutions beforethe sterilization and before carrying out process steps a) i) or a) ii).

Surfactants are preferably employed for these additives, with particularpreference for surfactants selected from the group consisting of: “Tween20 (INCI polysorbate 20, polyoxyethylene(20)sorbitan mono-laureate),Tween 80 (INCI polysorbate 80, polyoxyethylene(20)sorbitan monooleate),Cremophor RH 40 (macrogol/glycerol hydroxystearate 40, INCI PEG-40hydrogenated castor oil), Cremophor RH 60 (macrogol/glycerolhydroxystearate 60, INCI PEG-60 hydrogenated castor oil), Cremophor EL(macrogol/glycerol ricinoleate 35, poloxyl 35 castor oil) and solutolHS-15 (polyethylene glycol 15-hydroxystearate, macrogol/glycerolhydroxystearate 15)”. These and further additives are known to theskilled worker for example from “Fiedler—Lexikon der Hilfsstoffe fürPharmazie, Kosmetik und angrenzende Gebiete” (5th edition 2002).

Preparation of the solution/solutions for the procedure according toprocess steps a) i) and ii) without the addition of such additives whichincrease the solubility and/or suppress agglomeration, in particular gelformation, is preferred.

Process steps a) to d) of the process for producing sterile suspensionsof slightly soluble basic peptide complexes, and the process forproducing sterile lyophilizates of slightly soluble basic peptidecomplexes are preferably carried out under completely aseptic conditionsin the closed pharmaceutical production system familiar to the skilledworker. A production system of this type can for the purposes of thisinvention consist of one or more containers known to the skilled workerfrom his expert knowledge and suitable for aseptic pharmaceuticalproduction. These containers may moreover have any technically possiblevolume. It is moreover possible for process steps a) to d) to be carriedout in one and the same container or in two or more containers. In thecase of two or more containers, it is also possible for two or more ofthe process steps to be carried out in one container. In the case ofmore than one container, they may also be connected together in asuitable manner known to the skilled worker but nevertheless also beseparable from one another. The aseptic transfer of any materials, suchas, for example, suspensions and solutions of substances and mixtures ofsubstances, between two or more containers can likewise take place in amanner known to the skilled worker, such as, for example, throughapplication of pressure or reduced pressure (e.g. by pumps). Inaddition, a protective gas, e.g. nitrogen, can be used in such a processstep. Each container is additionally distinguished by being controllableto a desired specific temperature through the presence of a suitablecooling system, e.g. cooling jacket, using a suitable coolant. Coolingsystems and coolants are known to the skilled worker from his expertknowledge. The temperature which can be set by the cooling system forcarrying out process steps a) to d) is preferably 0-40° C., withpreference 2-25° C., particularly preferably 4-16° C. In addition, eachcontainer may optionally be movable, e.g. through the presence ofappropriate movable elements such as, for example, rollers, andoptionally have a removable device for mixing, preferably a stirrer, forexample a paddle stirrer as used in pharmaceutical production.

In a preferred embodiment, the processes according to the inventioncomprise carrying out process steps a) to d) in one and the samecontainer, it being possible for the container optionally to have aremovable device for mixing.

In a further preferred embodiment, the processes according to theinvention comprise carrying out process steps a) to d) in two or morecontainers, it being possible for each container optionally to have aremovable device for mixing, and it also being possible for two or moreof the process steps to be carried out in one container.

The mixing in process steps a) to d) of the process according to theinvention preferably takes place by stirring and can optionally becarried out continuously or at intervals. The mixing can, however, alsobe achieved diversely, e.g. by a plurality of mixing forms,simultaneously or sequentially, continuously or at intervals, forexample by pumping in a circulatory production system and in this casewith or without additional stirrers.

When carrying out the mixing, care must be taken that losses of yieldare minimized, for example there is no foam formation or losses of basicpeptide complex by increased deposition on the container walls, as maybe caused, for example, by too vigorous and rapid stirring. However, anappropriate optimization of the mixing can easily be effected by theskilled worker on the basis of his expert knowledge.

(Adequate) mixing will for example prevent agglomeration of theparticles of the slightly soluble basic peptide complex, as well as theformation of a solid sediment which cannot be resuspended, or can beonly partially resuspended, and inter alia, ensures that the suspensionof the slightly soluble basic peptide complex produced after processsteps a) to d) is homogeneous and can be administered parenterallydirectly.

It is also ensured inter alia that the suspension produced by theprocess for producing sterile suspensions suitable for parenteraladministration of slightly soluble basic peptide complexes byreconstituting the sterile lyophilizate with a sterile physiologicallytolerated reconstituting medium is likewise homogeneous and shows noagglomeration of the peptide particles and/or formation of a solidsediment which is not or is only partially resuspendable, and can alsobe administered parenterally directly.

Generation of the suspension of the slightly soluble basic peptidecomplex in step b) of the process for producing sterile suspensions ofslightly soluble basic peptide complexes takes place by reducing thesolubility of the basic peptide complex resulting after the reaction ofthe basic peptide with the carboxylic acid by adding diluent or mixtureof diluent in one or more steps until the slightly soluble basic peptidecomplex precipitates. To achieve a maximally complete, quantitativeprecipitation and minimization of losses of yield, it is necessary forthere to be careful selection and optimization of the solvent anddiluent used, or mixtures thereof, but also of the temperature. However,such selection and optimization experiments are known to the skilledworker from his expert knowledge and are simple to carry out, such as,for example, solubility determinations in the particular medium at, forexample, various temperatures or visual observation of the onset ofsuspension.

The continuous or stepwise separation process in step c) of the processfor producing sterile suspensions of slightly soluble basic peptidecomplexes is distinguished according to the invention by depletion ofsolvent or solvent mixture, of free non-peptide ions, of excesscarboxylic acid and of the additives which are optionally added toincrease the solubility and/or suppress agglomeration in the suspensionobtained in step b), with the liquid content of the suspension beingreduced and optionally further diluent or diluent being added in one ormore steps. The intention of the depletion is in particular to reducethe content of solvent or solvent mixture and of additives which areoptionally added to increase the solubility and/or suppressagglomeration, in particular gel formation, to an extent enablinglyophilization of the suspension of the slightly soluble basic peptidecomplex but also permitting direct parenteral administration of thesuspension or of the reconstituted lyophilizate of the slightly solublebasic peptide complex.

The extent of the solvent content with which freeze drying is stillpermitted depends on the particular solvent or solvent mixture.Characteristic limits are known to the skilled worker from the relevantspecialist literature. For example, the review by Teagarden and Baker(European Journal of Pharmaceutical Sciences, 2002, 15: 115-133)indicates various solvents or solvent mixtures (cosolvent systems) andvalues for their contents with and/or at which a freeze drying ofvarious pharmaceutical preparations took place. Thus, inter alia, theadvantages of a 20% (v/v) tert-butanol/water solvent mixture arediscussed, but at the same time it is also stated that with othersolvent mixtures, such as, for example, ethanol/water, n-propanol/wateror methanol/water, the content of the particular organic solvent appearsto be limited to a maximum of ten percent by volume for completesuccessful lyophilization.

The extent of the additives which increase the solubility and/orsuppress agglomeration, in particular gel formation, such as, forexample, surfactants, preferably Tween 20 (INCI polysorbate 20,polyoxyethylene (20) sorbitan monolaureate), Tween 80 (INCI polysorbate80, polyoxyethylene (20) sorbitan monooleate), Cremophor RH 40(macrogol/glycerol hydroxystearate 40, INCI PEG-40 hydrogenated castoroil), Cremophor RH 60 (macrogol/glycerol hydroxystearate 60, INCI PEG-60hydrogenated castor oil), Cremophor EL (macrogol/glycerol ricinoleate35, poloxyl 35 castor oil) and solutol HS-15 (polyethylene glycol15-hydroxystearate, macrogol/glycerol hydroxystearate 15), which stillpermits direct parenteral administration of the suspension or of thereconstituted lyophilizate of the slightly soluble basic peptide complexdepends on the particular peptide complex and on the particularpharmaceutical formulation, but is known to the skilled worker on thebasis of his expert knowledge. Thus, for example, numerouspharmaceutical additives which increase the solubility for various oraland parenteral formulations, and values for their contents, arediscussed in the review by Strickley (Pharmaceutical Research, 2004,31:201-230).

A depletion in the separation process of step c) can take placeaccording to the invention in two ways, by use of a filter or bycentrifugation, and can take place in one or more steps. This mayoptionally entail addition of further diluent or diluent mixture in oneor more steps, although further addition is preferred. In addition, theconcentration of the suspension of the slightly soluble basic peptidecomplex can, after the depletion has taken place, be adjusted byspecific addition of the diluent or diluent mixture and be higher than,the same as or lower than the initial concentration before depletion.Increasing the concentration of the suspension is preferred.

In the depletion by use of a filter, on the basis of the screen sizeand/or of the retention range of the filter the liquid content of thesuspension, the content of solvent or solvent mixture, of freenon-peptide ions, of excess carboxylic acid and of the additives whichare optionally added to increase the solubility and/or suppressagglomeration is reduced, but the particles of the slightly solublebasic peptide complex are retained. In this case, in particular thecontent of the solvent or solvent mixture and, where appropriate, alsoof the additives which increase the solubility and/or suppressagglomeration, in particular gel formation, is reduced by the dilutingeffect of the diluent or diluent mixture which is preferably added tothe particular extent which is known to the skilled worker and isdesired.

The term “filter” includes according to the invention all materialssuitable for the depletion in process step c), these being chemicallyinert towards the solvent and diluent or mixtures thereof and having aporous and/or sieve-like structure which makes it possible to retain theparticles of the suspension of the slightly soluble basic peptidecomplex and to deplete the liquid content of the suspension.

Filters for the purposes of this invention may be for example paperfilters, glass fiber filters, quartz fiber filters, depth-type filters,membranes, membrane filters, gauzes and filter gauzes. Preference isgiven to membranes, membrane filters, gauzes and filter gauzes. Examplesof suitable materials are: cotton, cellulose, cellulose, cellulose mixedesters, cellulose nitrate, cellulose acetate, regenerated cellulose,glass fibers, quartz microfibers, glass, borosilicate glass,borosilicate glass fibers, plastic, polymer, polyamide, polycarbonate,polypropylene, PTFE (Teflon), PVDF, metals, metal alloys, coated metals,sintered metals, ceramics. Preference is given to glass, ceramics,metals such as, for example, iron, nickel and chromium, metal alloys,such as, for example, stainless steel and brass, and coated metalsand/or metal alloys such as, for example, teflonized stainless steel.Stainless steel is particularly preferred. Further preferred materialsare plastic, polymer, polyamide, polycarbonate, polypropylene, PTFE(Teflon), PVDF, polysulfone and/or mixtures thereof.

By plastics are meant all known materials whose basic constituent aresynthetically or semisynthetically generated polymers. Technicalproperties of plastics, such as moldability, hardness, elasticity,fracture resistance, thermal and chemical stability can be varied withinwide limits through the selection of the starting material, theproduction process and the admixture of additives. Such moldingcompositions provided with additives are then characterized according toDIN EN ISO 1043 (thermoplastics) and according to DIN 7708 (thermosets).Semisynthetic plastics are produced by processing natural polymers (forexample cellulose to celluloid). Synthetic plastics are generated bypolymerization (polyaddition, polycondensation etc.) from a monomer. Allsuch plastics and polymers are to be regarded as belonging to theinvention.

Also preferred for the purposes of this invention are three-dimensionalfilters, i.e. filters whose separation surface extends intothree-dimensional space, such as, for example, a gauze or filter gauzemade of, for example, stainless steel, e.g. in the form of a cylinderwhich is open at the top and bottom (filter drum). Suchthree-dimensional filters may, because of their greatly enlarged surfacearea, lead to an improved separation in the separation process, it beingpossible for such an improvement to be manifested by one or moreadvantageous parameters, for example by a time-saving separationprocess, use of less starting material, greater yield of product, aproduct having improved properties, etc.

Thus, for example, use of a stainless steel gauze filter drum leads to atime saving by a factor of 2 to 3 when carrying out the separationprocess. Likewise, the use of one or more hollow fiber membranes madeof, for example, PVDF and/or polysulfone leads to a considerable timesaving.

The selection of the screen size and/or of the retention range of thefilter in this connection depends on the particle size distribution ofthe particles of the particular slightly soluble basic peptide complex.The particle size distribution varies for each individual peptidecomplex and can easily be determined by the skilled worker with the aidof his expert knowledge, e.g. by laser diffraction/laser diffractometry.The screen size and/or the retention range of the filter is to be chosenin this connection so that, on the one hand, the particles of theslightly soluble basic peptide complex are retained as completely aspossible, and thus losses of yield are minimized, but, on the otherhand, the filter does not become blocked and depletion of the liquidcontent of the suspension is impeded or, for example owing to anexorbitantly large expenditure of time and/or pressure to be applied, isnot or scarcely technically feasible. The selection is a simple matterfor the skilled worker on the basis of his expert knowledge and, forexample, by means of appropriate optimization experiments.

The terms “screen size” and “retention range” in relation to filtersinclude according to the invention both nominal values, i.e. for examplevalues stated by the manufacturer or on the basis of conventionalstandardization, natural values established by suitable measurementmethods, also averages in the case of size ranges, such as, for example,the average screen size. Preference is given for the purposes of thisinvention to a screen size and/or a retention range of 1-250 μm,preferably of 2-100 μm, particularly preferably of 3-30 μm. Preferenceis further given for the purposes of this invention to a screen sizeand/or a retention range of 0.1-250 μm, preferably of 0.1-100 μm andparticularly preferably of 0.1-30 μm.

In a preferred embodiment, the processes according to the inventioncomprise employing as filter a stainless steel gauze with a retentionrange of 1-250 μm, preferably of 2-100 μm and particularly preferably of3-30 μm, it also being possible for the stainless steel gauze to be athree-dimensional filter drum.

In a further preferred embodiment, the processes according to theinvention comprise the filter being selected from the group consistingof: “membrane, membrane filter” and is preferably one or more hollowfiber membranes made of materials selected from the group consisting of:“plastic, polymer, polyamide, polycarbonate, polypropylene, PTFE, PVDF,polysulfone” and preferably consists of PVDF and/or polysulfone, and isemployed with a screen size and/or retention range of 0.1-250 μm,preferably of 0.1-100 μm and particularly preferably of 0.1-30 μm.

In the separation process by use of a filter, the device for mixing,preferably a stirrer, is disposed in the corresponding container justabove the filter so that adequate mixing is achieved, the filter is notdamaged and/or its functioning impaired during the mixing, and blockingof the filter, as described above, is prevented. A correspondingoptimization is a simple matter for the skilled worker. This must alsobe taken into account on use of a three-dimensional filter, and in sucha case the device for mixing preferably extends into three-dimensionalspace, e.g. a three-dimensional rod stirrer on use of a stainless steelgauze filter drum. In addition, mixing by pumps is preferred in theseparation process after step c), and optionally in addition by anoptionally removable device for mixing, this device preferablyrepresenting a stirrer.

Depletion of the liquid content of the suspension by use of a filter canoptionally take place with application of pressure. It is possible inthis connection for the application of pressure to take place forexample continuously or at intervals and rising or falling. Care must betaken on application of pressure that the filter does not become blockedand depletion impeded or, for example owing to an exorbitantly largeexpenditure of time, is not or scarcely technically feasible. The way ofapplying pressure in aseptic pharmaceutical production is known to theskilled worker from his expert knowledge and can take place for examplethrough sterile-filtered compressed air or sterile-filtered nitrogen, ifnecessary using compression aids such as, for example, a compressor.Corresponding devices are attached to the container or containers.Application of pressure in the range from 0 to 2 bar is preferred forthe purposes of the invention.

On depletion by centrifugation, the liquid content of the suspension,the content of solvent or solvent mixture, of free non-peptide ions, ofexcess carboxylic acid and of the additives which are optionally addedto increase the solubility and/or suppress agglomeration is reduced bythe centrifugation in one or more steps to obtain the suspension of theslightly soluble basic peptide complex. This entails in particularreduction of the content of the solvent or solvent mixture and, whereappropriate, of the additives which increase the solubility and/orsuppress agglomeration, in particular gel formation, by the dilutingeffect of the diluent or diluent mixture which is preferably added tothe particular extent which is known to the skilled worker and desired.

The centrifugation can optionally take place horizontally or vertically.Sedimentation of the particles of the slightly soluble basic peptidecomplex takes place horizontally, i.e. perpendicular to the verticalrotation axis, on horizontal centrifugation (vertical rotation axis),and vertically, i.e. perpendicular to the horizontal rotation axis, onvertical centrifugation (horizontal rotation axis). The terms“horizontal” and “vertical” in connection with centrifuges, types ofcentrifuges, rotors and types of rotors relate, in contrast thereto, tothe particular rotation axis and not to the centrifugation and directionof sedimentation of the particles.

Centrifuges which can be used for the purposes of this invention are alltypes of centrifuge known to the skilled worker, in use inpharmaceutical production and suitable for aseptic production, preferredexamples being horizontal centrifuges, vertical centrifuges, horizontalpeeler centrifuges, vertical peeler centrifuges and pusher centrifuges.The term “centrifuge” also includes in this connection all accessorieswhich are known to the skilled worker and characterize a centrifuge,such as, for example, rotors and centrifugation containers or inserts,but also additional internals as detailed hereinafter. All known typesof rotor can be employed as rotor, e.g. preferably vertical andhorizontal rotors, swing-out rotors and fixed-angle rotors, it beingpossible for the rotors to be equipped with one or more centrifugationcontainers as insert, which may optionally be removable or a fixedcomponent of the particular rotor. In the case of more than onecentrifugation container, these may be inclined in relation to therotation axis in the particular rotor, with a preferred inclination offrom 0° to 90°.

Preferred centrifugation for the purposes of this invention ishorizontal centrifugation (vertical rotation axis). Preference isfurther given according to the invention to a centrifugation containeras optionally removable or fixed component of a vertical rotor with aninclination of 0° to the vertical rotation axis. Also preferred are twoor more centrifugation containers as optionally removable or fixedcomponent of a vertical rotor with an inclination of from 0° to 90° tothe vertical rotation axis.

The centrifuges consist of materials known to the skilled worker fromhis expert knowledge and suitable for aseptic pharmaceutical production,such as, for example, stainless steel, and may advantageously beadditionally prepared for the production in order for example to assistin preventing agglomeration of the particles of the slightly solublebasic peptide complex and/or formation of a solid sediment, such as, forexample, centrifugation containers of ground stainless steel with asliding behavior of the particles to be centrifuged which is improved bythe depth and alignment of the grinding.

The centrifuges may moreover have additional internals known to theskilled worker, preferably devices for mixing, such as, for example, astirrer, for adding solvent and/or diluent and/or suitablepharmaceutical excipients, carriers and/or bulking agents, such as, forexample, a filling pipe, for reducing the liquid content of thesuspension, such as, for example, a suction pipe, mechanical and/orpneumatic peeler devices. It is moreover possible for a plurality ofsuch additional internals and/or functions thereof also to be combinedin one device, such as, for example, a paddle stirrer which is hollowinside and serves simultaneously also as filling pipe and/or suctionpipe. Such additional internals may be optionally removable or a fixedcomponent of the centrifuge. The operation and/or actuation of suchadditional internals is known to the skilled worker and, in the case ofthe device for mixing, such as, for example, a stirrer, can take placefor example from outside through use of magnets.

The centrifugation speed or relative centrifugal force (RCF) can assumeall the conventional values known to the skilled worker, for example1-100 000 g or corresponding revolutions per minute. The centrifugationspeed or relative centrifugal force is to be chosen in this connectionso that the agglomeration of the particles of the slightly soluble basicpeptide complex, and the formation of a solid sediment which is not oris only partially resuspendable is prevented. A suitable centrifugationspeed or relative centrifugal force or ranges thereof can easily bedetermined by the skilled worker with the aid of his expert knowledge,e.g. by appropriate preliminary experiments.

Reduction of the liquid content of the suspension can optionally takeplace during the centrifugation or thereafter in one or more steps and,for example, by use of a suction pipe. It is preferred for the purposesof this invention to carry out the centrifugation at intervals, with thereduction in the liquid content of the suspension taking place in thepauses between the centrifugation steps and/or after the centrifugation,and ensuring during this that the suspension of the slightly solublebasic peptide complex is retained, i.e. for example not all the liquidcontent is removed, and losses of yield through, for example, tooextensive, rapid or imprecise removal of the supernatant, are minimized.

The preferred addition of the diluent or diluent mixture can optionallytake place during the centrifugation, after the centrifugation and/or,if the centrifugation is carried out at intervals, also in the pausesbetween the centrifugation steps in one or more steps, but preferably inthe pauses between the centrifugation steps and/or after thecentrifugation after the respective reduction of the liquid content ofthe suspension.

The mixing during the separation by centrifugation can optionally becarried out continuously or at intervals. Preference is given to mixingby stirring at intervals, such as, for example, in the pauses betweenthe centrifugation steps and after the centrifugation, after thereduction of the liquid content of the suspension, and during and/orafter the addition, taking place after this reduction, of the diluent ordiluent mixture. Additionally preferred for the purposes of thisinvention is a mixing which is brought about solely by acceleration andbraking of the centrifugation container(s) during the centrifugation,optionally with the assistance of an additional device for mixing.

The device for mixing is disposed so that adequate mixing of thesuspension of the slightly soluble basic peptide complex is ensured.Further additional internals such as, for example, to reduce the liquidcontent of the suspension, such as, for example, suction pipe, but alsocombined appliances described above with, for example, a mixing andremoval function, are to be disposed and/or designed so that losses ofyield through, for example, too extensive, rapid or imprecise removal ofthe supernatant are minimized. The dispositions suitable in each casecan easily be established by the skilled worker through appropriateexperiments.

In step d) of the process according to the invention it is possibleoptionally to add to the suspension or the lyophilizate suitablepharmaceutical excipients, carriers and/or bulking agents such as, forexample, mannitol, sorbitol, xylitol, trehalose, glucose, solublestarch, sucrose and saccharose. Addition of these excipients, carriersand/or bulking agents can take place as sterile solid and/or as sterilesolution.

Preference is given for the purposes of this invention to addition ofmannitol, sorbitol, xylitol, trehalose, glucose, soluble starch, sucroseand/or saccharose as sterile solution in step d) of the process forproducing sterile suspensions of slightly soluble basic peptidecomplexes, with the mixing preferably taking place by stirring.Preference is further given to the addition of mannitol, sorbitol,xylitol, trehalose, glucose, soluble starch, sucrose and/or saccharoseas sterile solid in the process for producing sterile lyophilizates ofslightly soluble basic peptide complexes, it being possible for theaddition to take place before, during and/or after the lyophilizationand optionally with mixing.

In a preferred embodiment, the process for producing sterile suspensionscomprises

-   a) mixing a sterile solution comprising the acetate salt of an LHRH    antagonist selected from the group consisting of: “cetrorelix,    teverelix, ozarelix (D-63153)” and the salt of a carboxylic acid    selected from the group consisting of: “embonic acid, citric acid,    palmitic acid” in an aqueous ethanolic solvent mixture having an    ethanol content of from 50 to 90% (m/m), in particular around 70%    (m/m),-   b) generating, by mixing and addition of water as diluent in one or    more steps, a suspension of the slightly soluble basic peptide    complex of the basic peptide with the carboxylic acid, where the    molar ratio of basic peptide to carboxylic acid in the slightly    soluble basic peptide complex assumes a value of between 2:1 and    1:2,-   c) depleting, while mixing and with further addition of water as    further diluent in one or more steps and optionally with application    of pressure, ethanol, free non-peptide ions and excess carboxylic    acid in the suspension obtained in step b) through use of a    stainless steel gauze filter having a retention range of 2-100 μm,    preferably of 3-30 μm, and reducing the liquid content of the    suspension, and-   d) adding, while mixing the sterile suspension, thus obtained, of    the slightly soluble basic peptide complex, a mannitol as bulking    agent-containing (sterile) solution,    where process steps a) to d) are carried out in one and the same or    two containers, and the mixing is brought about by a suitable    stirrer.

In a further preferred embodiment, the process for producing sterilesuspensions comprises employing as filter in step c) one or more hollowfiber membranes which prefreably consist of PVDF and/or polysulfone andhave a screen size and/or retention range of 0.1-100 μm, preferably of0.1-30 μm, in particular 0.2 μm, and the mixing being brought about bypumps and optionally additionally by an optionally removable device formixing, this device preferably representing a stirrer.

In a further preferred embodiment, the process for producing sterilelyophilizates comprises lyophilizing the sterile suspension obtained instep d) of the process for producing sterile suspensions according tothe preferred embodiments described above.

In a further preferred embodiment, the process for producing sterilesuspensions suitable for parenteral administration comprisesreconstituting with water for injections the lyophilizate obtained bythe preferred embodiment described above of the process for producingsterile lyophilizates.

In the process for producing sterile lyophilizates of slightly solublebasic peptide complexes, the sterile suspension of the slightly solublebasic peptide complex which is obtained in steps c) or d) of the processfor producing sterile suspensions of slightly soluble basic peptidecomplexes can be lyophilized and optionally pharmaceutical excipients,carriers and/or bulking agents be added. Lyophilization of the sterilesuspension of the slightly soluble basic peptide complex with optionaladdition of the suitable pharmaceutical excipients, carriers and/orbulking agents takes place in a way known to the skilled worker from hisexpert knowledge with the assistance of a standard freeze-drying systemwhich is suitable for aseptic pharmaceutical production. The dispensingof the suspension, which is necessary before the lyophilization, intosuitable vials is likewise known to the skilled worker and takes placeusing a standard dispensing system which is suitable for asepticpharmaceutical production which is to be understood according to theinvention as also being container and component of the closed productionsystem.

In the process for producing sterile suspensions, suitable forparenteral administration, of slightly soluble basic peptide complexes,the sterile lyophilizate of the slightly soluble basic peptide complexwhich has been obtained by the process for producing sterilelyophilizates of slightly soluble basic peptide complexes can bereconstituted with a sterile physiologically tolerated reconstitutingmedium. Such reconstituting media are known to the skilled worker. Thereconstituting media used for the purposes of this invention arepreferably to be only those which contain no additives which increasethe viscosity and/or otherwise increase the stability of the suspensionand/or induce allergic reactions, but especially nocarboxymethylcellulose (CMC). The preferred reconstituting medium issterile water, particularly preferably water for injections.

The sterile suspensions produced according to the invention by theprocess described above for producing sterile suspensions of slightlysoluble basic peptide complexes, but also the process for producingsterile suspensions of slightly soluble basic peptide complexes suitablefor parenteral administration are surprisingly distinguished inter aliaby remaining stable over a period of at least 2 hours, preferably 4, 8,12, 24, 36, 48 and/or 72 hours, but usually also for several days andweeks, and without requiring the addition of additives which increasethe viscosity and/or otherwise increase the stability of the suspension,for example carboxymethylcellulose (CMC) which, in some circumstances,may also induce allergic reactions.

The terms “stable” and “stability” in relation to the suspension of theslightly soluble basic peptide complex mean according to the inventionthat no visually recognizable separation of the suspension into mutuallyseparate solid and liquid phases (physical stability) takes place duringthe stability period and without mixing; on the contrary, the suspensionremains homogeneous. In addition, the terms “stable” and “stability”mean in this connection that neither the peptide component of the basicpeptide complex nor the carboxylic acid component undergoes chemicaldecomposition (chemical stability).

Assessment and assignment of the criteria “stable” and “stability” inrelation to the suspension of the slightly soluble basic peptide complexis a simple matter for the skilled worker on the basis of his expertknowledge. Thus, the start of separation can be determined for examplevisually through the start of sediment formation and/or through theoccurrence of homogeneity, i.e. regions of visually detectabledifferences in particle density. Chemical stability can be demonstratedby suitable chromatographic methods, for example by HPLC.

In addition, sterile suspensions produced according to the invention bythe processes described above for producing sterile suspensions ofslightly soluble basic peptide complexes and processes for producingsterile suspensions, suitable for parenteral administration, of slightlysoluble basic peptide complexes are surprisingly distinguished by theirparticles having a more advantageous morphology, for example surfacearea, form, shape, size and/or specific density.

The morphology of the particles can for the purposes of this inventionsurprisingly and advantageously be controlled in a targeted manner bysuitable variations of the conditions for the generation of thesuspensions by adding the diluent or diluent mixture, for example by thespeed of mixing, speed of addition, temperature, nature of the mixingdevice (e.g. type of stirrer), mixing time, ratio of basic peptide tocarboxylic acid etc. Such a targeted possibility for control is asubstantial advantage of the processes according to the inventioncompared with the processes described in the prior art and leads toadvantageous effects, e.g. those described herein, of the suspensionsaccording to the invention. The skilled worker can easily optimize theprocess conditions for such a targeted control for the purposes of thisinvention on the basis of his expert knowledge, for example by carryingout appropriate experimental preliminary tests.

It has also been found, surprisingly, that a change in the morphology ofthe particles influences the release of the basic peptide (activeingredient) from the administered suspension of the slightly solublebasic peptide complex, for example through the presumably differentformation of a more or less dense gel network, from which the activeingredient is dissolved at different rates.

The sterile suspensions produced according to the invention by theprocesses described above for producing sterile suspensions of slightlysoluble basic peptide complexes and processes for producing sterilesuspensions of slightly soluble basic peptide complexes suitable forparenteral administration is also surprisingly distinguished by theparticles of the slightly soluble basic peptide complex which havesedimented not agglomerating and not forming any sediment which is notor is only partially resuspendable, and by a stable suspension beingobtained again by simple mixing, such as, for example, brief shaking orstirring, certainly even after several weeks and months.

In addition, the sterile suspension produced according to the inventionby the process for producing sterile suspensions of slightly solublebasic peptide complexes, and the sterile suspensions produced by theprocess for producing sterile suspensions, suitable for parenteraladministration, of slightly soluble basic peptide complexes aresurprisingly distinguished by being amenable to direct parenteraladministration, i.e. not requiring further processing or treatment forparenteral administration, and being amenable to administration withoutfurther additions such as, for example, additives which increase theviscosity and/or otherwise increase the stability of the suspension andin particular without carboxymethylcellulose (CMC).

The sterile suspensions produced according to the invention are furthersurprisingly distinguished by showing improved active ingredient release(drug release), it being possible for this improvement to represent bothan increase in the absolute amount of cumulatively released basicpeptide such as, for example, cetrorelix, and to be an improvedcontrolled release, for example a release of basic peptide which iscontinuously increased and/or more uniform over a particular period, orelse a prolongation of the period of active ingredient release. Thus, animproved controlled release of the sterile suspensions producedaccording to the invention may be characterized for example by a fastrelease of the carboxylic acid component from the basic peptide complex,whereas the peptide component (the active ingredient) is advantageouslydelivered from the complex in a controlled manner over a prolongedperiod.

The sterile suspensions produced according to the invention by theprocess for producing sterile suspensions of slightly soluble basicpeptide complexes and processes for producing sterile suspensions,suitable for parenteral administration, of slightly soluble basicpeptide complexes are additionally surprisingly distinguished by showingan improved local tolerability on subcutaneous parenteraladministration.

In addition, the suspensions produced according to the inventionsurprisingly show a more advantageous hormone suppression. Thus, forexample, in the treatment of endometriosis or uterine myomas in women, areliable, therapeutically effective and controlled reduction in theestradiol level is achieved without chemical castration being broughtabout and hormone withdrawal manifestation which are disadvantageous forthe patients recurring. In the treatment of benign prostate hyperplasia(BPH) in men, for example, a pronounced, deeper and longer-lastingreduction in the testosterone level is achieved, but likewise withoutreaching the castration level and/or causing disadvantageous hormonewithdrawal manifestations.

The sterile lyophilizate of the slightly soluble basic peptide complexobtained by the process for producing sterile lyophilizates of slightlysoluble basic peptide complexes is surprisingly distinguished by beingdirectly reconstitutable without further processing or treatment with asterile physiologically tolerated reconstituting medium, and theresulting sterile suspension being amenable to direct parenteraladministration.

The sterile suspensions produced according to the invention, and thesterile lyophilizate may also be component of pharmaceuticalformulations for parenteral administration, these comprising at leastone sterile suspension, produced according to the invention, of aslightly soluble basic peptide complex or at least one sterilelyophilizate of a slightly soluble basic peptide complex.

In addition, the sterile lyophilizates produced according to theinvention may also be component of a kit which includes at least onesterile lyophilizate of a slightly soluble basic peptide complex and atleast one sterile physiologically tolerated reconstituting medium.

The sterile suspensions and sterile lyophilizates, produced according tothe invention, of slightly soluble basic peptide complexes, and thepharmaceutical formulations for parenteral administration can be used asmedicaments for the treatment and prophylaxis of diseases andpathological states in mammals, especially in humans.

They are preferably used for the treatment of benign or malignantneoplastic diseases, in male fertility control, in hormone therapy,hormone-dependent neoplastic diseases, female sub- or infertility, forin vitro fertilization, for female contraception, for the treatment ofHIV infections, for the treatment of neurological or neurodegenerativedisorders, and for protection from side effects due to chemotherapy, andparticularly preferably for the treatment of prostate cancer, benignprostate hyperplasia (BPH), endometriosis, uterine fibroids, uterinemyomas, breast cancer, premenopausal breast cancer, uterine cancer,endometrial cancer, cervical cancer, ovarian cancer, precocions puberty,hirsutism, polycystic ovary syndrome, AIDS, ARC (AIDS related complex),Karposi sarcoma, tumors originating from the brain and/or nervous systemand/or meninges (see WO 99/01764), dementia and Alzheimer's.

BRIEF DESCRIPTION OF THE DRAWINGS

These show:

FIG. 1: A longitudinal section through a closed production systemaccording to the invention for depletion by means of filter separation.

FIG. 2: A longitudinal section through a production system according tothe invention for depletion by means of centrifugation.

FIG. 3: A longitudinal section through a closed production systemaccording to the invention for depletion by means of three-dimensionalfilter separation.

FIG. 4: A diagrammatic representation of a closed production systemaccording to the invention for depletion by means of hollow fibermembrane filter separation.

DESCRIPTION OF THE PREFERRED DESIGN OF APPARATUS

FIG. 1 depicts a longitudinal section through a container 1 which isemployed to produce the sterile suspensions of slightly soluble basicpeptide complexes.

As is evident in FIG. 1, the container 1 is used to react the startingmaterials dissolved in the sterile solution after step a) i) or thesterile solutions after step a) ii) of the process. The container 1 issurrounded by a cooling system 2 a, 2 b to adjust and maintain thereaction temperature, with provision of an entry 2 a and exit 2 b forthe cooling medium. Mixing of the reaction components with furthersolvents or diluents and additives in process steps a) to d) takes placewith a stirrer 3. The depletion of solvent or solvent mixture, ions,excess carboxylic acid and additives from the suspension of the slightlysoluble basic peptide complex obtained from the reaction can be achievedwith a filter 4. The stirrer 3 is disposed just above the filter 4. Theapertures disposed in the upper region of the container 1 serve ascharging aperture 5 or for applying pressure 6. If the depletion iscarried out by means of a filter 4, the resulting suspension isdischarged through a suspension outlet 7 and the reduced liquid contentof the suspension is discharged through a liquid outlet 8. An elementwhich is disposed on the container 1 and has a hinge 10 serves to openthe lower part of the apparatus. The container is fixed in a frame withrollers 11 for mobile use of the apparatus.

In an embodiment depicted in FIG. 2 it is possible to dispense with useof a filter 4 if the depletion of solvent or solvent mixture, ions,excess carboxylic acid and additives from the resulting suspension ofthe slightly soluble basic peptide complex takes place bycentrifugation.

FIG. 2 shows a longitudinal section through a centrifugation system in adesign with vertical rotor axis 12 and resting on a fastening 13 of therotor. The container 1 of a closed production system is rotatablymounted inside a cooling system 2 a, 2 b. The cooling system 2 a, 2 b isdisposed outside the container 1. In this case, the container 1 issubjected to centrifugation. In this embodiment, the stirrer 3 isdisposed above the base of the container. Besides the charging aperture5, a suction pipe 9 is disposed to draw off the liquid phase and may beoptionally removable or a fixed installation.

FIG. 3 depicts a longitudinal section through a container 1 which isemployed to produce the sterile suspensions of slightly soluble basicpeptide complexes by means of three-dimensional filter separation. As isevident from FIG. 3, the container 1 is used for reacting the startingmaterials dissolved in the sterile solution after step a) i) or thesterile solutions after step a) ii) of the process. The container 1 issurrounded by a cooling system 2 a, 2 b to adjust and maintain thereaction temperature, where there is provision of an entry 2 a and exit2 b for the cooling medium. Mixing of the reaction components withfurther solvents or diluents and additives in process steps a) to d)takes place with a stirrer 3, this stirrer advantageously being athree-dimensional rod stirrer. The depletion of solvent or solventmixture, ions, excess carboxylic acid and additives from the suspensionof the slightly soluble basic peptide complex obtained from the reactioncan be achieved with a three-dimensional filter 4 (preferably filterdrum). The apertures disposed in the upper region of the container 1serve as charging aperture 5 or for applying pressure 6. If thedepletion is carried out by means of a filter 4, the resultingsuspension is discharged through a suspension outlet 7 and the reducedliquid content of the suspension is discharged through a liquid outlet8. Elements disposed on the container 1 and having a hinge 10 are usedto open the apparatus.

In an embodiment depicted in FIG. 4 by means of hollow fiber membranefilter separation it is possible to dispense with the use of a filter inthe initial container 1 if the depletion of solvent or solvent mixture,ions, excess carboxylic acid and additives from the resulting suspensionof the slightly soluble basic peptide complex takes place in a separatehollow fiber membrane filter module 4.

FIG. 4 shows a diagrammatic representation of a closed production systemaccording to the invention for depletion by means of hollow fibermembrane filter separation. The container 1 is used to react thestarting materials dissolved in the sterile solution after step a) i) orthe sterile solutions after step a) ii) of the process. The container 1is surrounded by a cooling system 2 a, 2 b to adjust and maintain thereaction temperature, with provision of an entry 2 a and exit 2 b forthe cooling medium. Mixing of the reaction components with furthersolvents or diluents and additives in process steps a) to d) takes placeby pumping through the closed production system by means of pump 14 andoptionally additionally by a stirrer 3 optionally located in thecontainer 1. The depletion of solvent or solvent mixture, ions, excesscarboxylic acid and additives from the suspension of the slightlysoluble basic peptide complex obtained from the reaction can be achievedwith a hollow fiber membrane filtration module 4. The apertures disposedin the upper region of the container 1 serve as charging aperture 5 orfor applying pressure 6. If the depletion is carried out by means of ahollow fiber membrane filter module 4, the resulting suspension isdischarged through a suspension outlet 7 and the reduced liquid contentof the suspension is discharged through exit from the hollow fibermembrane filter module (8).

FIG. 5: Particle Size Distribution of the Particles of a Suspension ofCetrorelix Embonate (2:1)

FIG. 5 shows the particle size distribution of the particles of asuspension of cetrorelix embonate which was produced as in Example 1 andmeasured as in Example 10. The percentage content of the particles (% byvolume) is depicted as cumulative plot as a function of the particlediameter in Am.

FIG. 6: In Vitro Active Ingredient Release from Various CetrorelixEmbonate Formulations

FIG. 6 depicts the active ingredient release from various cetrorelixembonate formulations in physiological Ringer's solution according tothe in vitro release carried out in Example 12. The respectivecumulative amount of cetrorelix released in mg (“cetrorelix (mg)released cumulated”) is shown as a function of the time in hours (“time(h)”). The following formulations (in each case independent duplicates)were used: (i) P85P002A (suspension according to the invention), (ii)DJ5 [cetrorelix embonate (1:1.6) microparticle formulation according toDE 43 42 092 and Felberbaum et al. (1998)], (iii) 9612-002/05-g(suspension obtained according to DE 100 40 700).

FIG. 7: Comparison of Testosterone Suppression

FIG. 7 shows the testosterone suppression as found in Example 13. Thelevels are depicted normalized to the respective initial levels at thetime of administration (% of baseline) (week 0=100%) and indicated forweeks 0, 1 and 2 [time (weeks)] (study 3107: suspension produced andadministered according to DE 100 40 700; study JAP: suspension producedand administered according to the invention).

The contents of all cited references and patents are hereby incorporatedby reference. The invention is explained in more detail by means of thefollowing examples without, however, being restricted thereto.

EXAMPLES Example 1 Production of a Sterile Suspension of CetrorelixEmbonate (2:1) and of a Sterile Lyophilizate of 30 mg of CetrorelixEmbonate Using the Separation Process by Means of a Filter

123.7 g of cetrorelix acetate were added stepwise with continuousstirring to 3182 g of water for injection in a suitable vessel anddissolved. 10270 g of 96% (v/v) ethanol were then added with stirring.The ethanol content was subsequently adjusted to 70% (m/m) with waterfor injections. 17.0 g of disodium embonate were then added withcontinuous stirring until the disodium embonate had completely dissolved(=solution 1). 12963 g of solution 1 were subsequently transferred withthe aid of a sterilizing filter (0.22 μm) into a container (see FIG. 1).The container was cooled to a temperature of 11±3° C. and kept at thistemperature throughout the process. About 26544 g of precooled water forinjections (11±3° C.) were then filtered sterile into the containerwhile stirring, and a suspension of cetrorelix embonate was produced(=suspension 1). Suspension 1 was stirred for 20-30 min after addition.The sterile outlet valve (see FIG. 1, liquid outlet 8) was subsequentlyopened, and the suspension was concentrated through the stainless steelgauze (nominal pore size: 5 μm), employed, initially without pressureand later by applying a low pressure (<0.2 bar). After about 22580 g ofclear filtrate had been discharged, the valve was closed. Thereafter,about 13737 g of precooled water for injections (11±3° C.) were againfiltered sterile into the container while stirring (=suspension 2).Suspension 2 was filtered for 20-30 minutes after addition. The sterileoutlet valve was then opened again, and the suspension was concentratedas described previously. After about 13910 g of clear filtrate had beendischarged, the outlet valve was closed and about 7686 g of precooledwater for injections (11±3° C.) were again filtered sterile into thecontainer with stirring (=suspension 3). The suspension was stirred for20-30 min after addition. The sterile outlet valve was then againopened, and the suspension was concentrated as described previously.After about 15110 g of clear filtrate had been discharged, the outletvalve was closed. 8280 g of this suspension were then transferred fromthe first container into a further sterile container and then 8310 g ofa 4% (m/m) mannitol solution were filtered sterile into the furthercontainer while stirring (=suspension 4). Addition was followed bystirring for 10-15 min, and then the final suspension 4 was dispensedthrough the suspension outlet valve (see, for example, FIG. 1,suspension outlet 7) into 10R glass vials. The dispensing solutioncontains not more than 10% ethanol. The molar ratio of cetrorelix toembonate was 2:1. The filled vials (about 3000) were placed in thelyophilizer, frozen at about −45° C. and lyophilized in vacuo at a platetemperature rising from −45° C. to +20° C. in the primary drying and atabout 25° C. in the secondary drying. The freeze-drying system was thenflushed with sterile nitrogen, and the vials were closed with suitablestoppers in the system and then crimp-capped. The lyophilizate wasreconstituted by using 2 ml of water for injections per vial. Thesuspension obtained by gentle swirling can be administered s.c. or i.m.

Example 2 Production of a Sterile Suspension of Teverelix Embonate (2:1)and of a Sterile Lyophilizate of 30 mg of Teverelix Embonate Using theSeparation Process by Means of a Filter

115.3 g of teverelix acetate are added stepwise with continuous stirringto 3006 g of water for injection in a suitable vessel and dissolved.9827 g of 96% (v/v) ethanol are then added with stirring. The ethanolcontent is subsequently adjusted to 70% (m/m) with water for injections.15.7 g of disodium embonate are then added with continuous stirringuntil the disodium embonate had completely dissolved (=solution 1).11802 g of solution 1 are subsequently transferred with the aid of asterilizing filter (0.22 μm) into a container (see FIG. 1). Thecontainer is cooled to a temperature of 11±3° C. and kept at thistemperature throughout the process. About 24203 g of precooled water forinjections (11±3° C.) are then filtered sterile into the container whilestirring, and a suspension of teverelix embonate was produced(=suspension 1). Suspension 1 is stirred for 20-30 min after addition.The sterile outlet valve (see FIG. 1, liquid outlet 8) is subsequentlyopened, and the suspension is concentrated through the stainless steelgauze (nominal pore size: 5 μm), employed, initially without pressureand later by applying a low pressure (<0.2 bar). After about 18987 g ofclear filtrate have been discharged, the valve is closed. Thereafter,about 11000 g of precooled water for injections (11±3° C.) are againfiltered sterile into the container while stirring (=suspension 2).Suspension 2 is filtered for 20-30 minutes after addition. The sterileoutlet valve is then opened again, and the suspension is concentrated asdescribed previously. After about 11000 g of clear filtrate have beendischarged, the outlet valve is closed and about 10107 g of precooledwater for injections (11±3° C.) are again filtered sterile into thecontainer with stirring (=suspension 3). The suspension was stirred for20-30 min after addition. The sterile outlet valve is then again opened,and the suspension is concentrated as described previously. After about18303 g of clear filtrate have been discharged, the outlet valve isclosed. 8262 g of this suspension are then transferred from the firstcontainer into a further sterile container and then 3187 g of a 4% (m/m)mannitol solution are filtered sterile into the further container whilestirring (=suspension 4). Addition is followed by stirring for 10-15min, and then the final suspension 4 is dispensed through the suspensionoutlet valve (see, for example, FIG. 1, suspension outlet 7) into 10Rglass vials. The dispensing solution contains not more than 10% ethanol.The molar ratio of teverelix to embonate is 2:1. The filled vials (about3000) are placed in the lyophilizer, frozen at about −45° C. andlyophilized in vacuo at a plate temperature rising from −45° C. to +20°C. in the primary drying and at about 25° C. in the secondary drying.The freeze-drying system is then flushed with sterile nitrogen, and thevials are closed with suitable stoppers in the system and thencrimp-capped. The lyophilizate is reconstituted by using 2 ml of waterfor injections per vial. The suspension obtained by gentle swirling canbe administered s.c. or i.m.

Example 3 Production of a Sterile Suspension of D-63153 Embonate (2:1)and of a Sterile Lyophilizate of 30 mg of D-63153 Embonate Using theSeparation Process by Means of a Filter

118 g of D-63153 acetate are added stepwise with continuous stirring to3095 g of water for injection in a suitable vessel and dissolved. 10116g of 96% (v/v) ethanol are then added with stirring. The ethanol contentis subsequently adjusted to 70% (m/m) with water for injections. 16.2 gof disodium embonate are then added with continuous stirring until thedisodium embonate has completely dissolved (=solution 1). 12186 g ofsolution 1 are subsequently transferred with the aid of a sterilizingfilter (0.22 μm) into a container (see FIG. 1). The container is cooledto a temperature of 11±3° C. and kept at this temperature throughout theprocess. About 24972 g of precooled water for injections (11±3° C.) arethen filtered sterile into the container while stirring, and asuspension of D-63153 embonate is produced (=suspension 1). Suspension 1is stirred for 20-30 min after addition. The sterile outlet valve (seeFIG. 1, liquid outlet 8) is subsequently opened, and the suspension isconcentrated through the stainless steel gauze (nominal pore size: 5μm), employed, initially without pressure and later by applying a lowpressure (<0.2 bar). After about 20140 g of clear filtrate have beendischarged, the valve is closed. Thereafter, about 11900 g of precooledwater for injections (11±3° C.) are again filtered sterile into thecontainer while stirring (=suspension 2). Suspension 2 is filtered for20-30 minutes after addition. The sterile outlet valve is then openedagain, and the suspension is concentrated as described previously. Afterabout 11900 g of clear filtrate have been discharged, the outlet valveis closed and about 9263 g of precooled water for injections (11±3° C.)are again filtered sterile into the container with stirring (=suspension3). The suspension is stirred for 20-30 min after addition. The sterileoutlet valve is then again opened, and the suspension is concentrated asdescribed previously. After about 17186 g of clear filtrate have beendischarged, the outlet valve is closed. 8535 g of this suspension arethen transferred from the first container into a further sterilecontainer and then 3283 g of a 4% (m/m) mannitol solution are filteredsterile into the further container while stirring (=suspension 4).Addition is followed by stirring for 10-15 min, and then the finalsuspension 4 is dispensed through the suspension outlet valve (see FIG.1, suspension outlet 7) into 10R glass vials. The dispensing solutioncontains not more than 10% ethanol. The molar ratio of D-63153 toembonate is 2:1. The filled vials (about 3000) are placed in thelyophilizer, frozen at about −45° C. and lyophilized in vacuo at a platetemperature rising from −45° C. to +20° C. in the primary drying and atabout 25° C. in the secondary drying. The freeze-drying system is thenflushed with sterile nitrogen, and the vials are closed with suitablestoppers in the system and then crimp-capped. The lyophilizate isreconstituted by using 2 ml of water for injections per vial. Thesuspension obtained by gentle swirling can be administered s.c. or i.m.

Example 4 Production of a Sterile Suspension of Cetrorelix Embonate(2:1) and of a Sterile Lyophilizate of 30 mg of Cetrorelix EmbonateUsing the Separation Process by Means of Centrifugation

1.85 g of cetrorelix acetate were dissolved in 47 ml of water forinjections in a suitable vessel while stirring. Then 128 ml of 96% (v/v)ethanol were added while stirring, and subsequently the ethanol contentwas adjusted to 70% (m/m) with water for injections (=solution 1). 0.24g of disodium embonate was added to 150 ml of this solution 1 whilestirring. Stirring was continued for 10-15 min after the addition untilthe disodium embonate had completely dissolved. The centrifuge (see alsoFIG. 2) was loaded with in each case 8-10 containers and subsequently2.4 ml portions of this solution were filtered sterile (0.22 μm) into acentrifuge container. 5.6 ml of water for injections were then added toeach centrifugation container while stirring, and a suspension wasproduced (=suspension 1). The stirrer was switched off after stirringfor 10 min. The complete centrifugation apparatus was controlled in atemperature range of 4-16° C. throughout the production process, and thecentrifugation was carried out at 9,500 g for about 0.5 minutes. Then 5ml of the clear supernatant solution were removed sterile by means of asuction pipe from each centrifugation container, and about 5 ml of waterfor injections were again added to the individual containers and stirred(=suspension 2). Centrifugation was then carried out at about 13,000 gfor about 0.5 minutes. Subsequently, 5 ml portions of the supernatantsolution were removed sterile by means of a suction pipe from eachcentrifugation container, and about 5 ml of water for injections wasagain added to the individual containers and stirred (=suspension 3).Finally, suspension was then carried out at about 13,000 g for about 0.5minute, and 5 ml portions of supernatant solution were removed sterilefrom each centrifugation container. 2 ml of a 12.5% (w/w) sterilemannitol solution were then added to the suspension in eachcentrifugation container while stirring to result in an isotonicsuspension with 5% mannitol (=suspension 4). The final suspensions 4were then dispensed aseptically from the centrifugation containers into10R vials (5 ml portions). The described procedure was repeated with newcentrifugation containers until all of solution 1 was reacted. The molarratio of cetrorelix to embonate was 2:1. The resulting approximately 60vials were placed in the lyophilizer, frozen at about −45° C. andlyophilized in vacuo at a plate temperature rising from −45° C. to +20°C. in the primary drying and at about 25° C. in the secondary drying.The freeze-drying system was then flushed with sterile nitrogen and thevials were closed with suitable stoppers in the system and subsequentlycrimp-capped. 2 ml of water for injections were used to reconstitute thelyophilizate per vial.

The suspension obtained by gentle swirling can be administered s.c. ori.m.

Example 5 Production of a Sterile Suspension of Cetrorelix Palmitate(1:1) and of a Sterile Lyophilizate of 30 mg of Cetrorelix PalmitateUsing the Separation Process by Means of Centrifugation

1.85 g of cetrorelix acetate were dissolved in 47 ml of water forinjections in a suitable vessel while stirring. Then 128 ml of 96% (v/v)ethanol were added while stirring, and subsequently the ethanol contentwas adjusted to 70% (m/m) with water for injections (=solution 1). 0.3 gof palmitic acid was added to 150 ml of this solution 1 while stirring(=solution 2). Stirring was continued for 10-15 min after the addition.The centrifuge was loaded with in each case 8-10 containers andsubsequently 2.4 ml of this solution 2 in each case were filteredsterile (0.22 μm) into one of the centrifuge containers. 5.6 ml of waterfor injections were then added while stirring, and a suspension wasproduced (=suspension 1). Further processing was then carried out asdescribed in Example 4, but the centrifugations were each carried out atabout 19,000 g for about 15 min each time. The molar ratio of cetrorelixto palmitate was 1:1. The lyophilizate was reconstituted by using 2 mlof water for injections per vial. The suspension obtained by gentleswirling can be administered s.c. or i.m.

Example 6 Production of a Sterile Suspension of Cetrorelix Citrate (1:1)and of a Sterile Lyophilizate of 30 mg of Cetrorelix Citrate Using theSeparation Process by Means of Centrifugation

1.85 g of cetrorelix acetate were dissolved in 47 ml of water forinjections in a suitable vessel while stirring. Then 128 ml of 96% (v/v)ethanol were added while stirring, and subsequently the ethanol contentwas adjusted to 70% (m/m) with water for injections (=solution 1). 0.24g of citric acid monohydrate was added to 150 ml of this solution 1while stirring (=solution 2). Stirring was continued for 10-15 min afterthe addition. The centrifuge was loaded with in each case 8-10containers and subsequently 2.4 ml of this solution 2 in each case werefiltered sterile (0.22 μm) into one of centrifuge containers. 5.6 ml ofwater for injections were then added while stirring, and a suspensionwas produced (=suspension 1). Further processing was then carried out asdescribed in Example 4, but the centrifugations were each carried out atabout 19,000 g for about 15 min each time. The molar ratio of cetrorelixto citrate was 1:1. The lyophilizate was reconstituted by using 2 ml ofwater for injections per vial. The suspension obtained by gentleswirling can be administered s.c. or i.m.

Example 7 Production of a Sterile Suspension of Cetrorelix Embonate(2:1) and of a Sterile Lyophilizate of 30 mg of Cetrorelix EmbonateUsing the Separation Process by Means of Three-Dimensional FilterSeparation

44.02 g of cetrorelix acetate are added stepwise with continuousstirring to about 1149 g of water for injections in a first suitablevessel and are dissolved. Then about 3798 g of 92% (m/m) ethanol areadded while stirring. Subsequently, the ethanol content is adjusted to70% (m/m) with 0.17 g of water for injections (=solution 1). 6.15 g ofdisodium embonate [86% (m/m)] is then added while stirring continuouslyuntil the disodium embonate has dissolved completely (=solution 2).4850.0 g of solution 2 are then transferred with the aid of asterilizing filter (0.22 m) in a further container (see FIG. 3). Thecontainer is cooled to a temperature of 11+/−3° C. and maintained atthis temperature throughout the process. About 9700 g of precooled waterfor injections (11+/−3° C.) are then filtered sterile into the containerwhile stirring, and a suspension of cetrorelix embonate is generated(=suspension 1). After the addition, suspension 1 is stirred for 20-30min. The sterile outlet valve (see FIG. 3, liquid outlet 8) is thenopened, and the suspension is concentrated, initially under atmosphericpressure and later by applying a slight pressure (<0.2 bar) through thestainless steel gauze employed (three-dimensional filter drum, nominalpore size: 3 μm). After about 8639 g of clear filtrate have beendischarged, the valve is closed. Then a further approx. 5523 g ofprecooled water for injections (11+/−320 C.) are filtered sterile intothe container while stirring (=suspension 2). After the addition,suspension 2 is stirred for about 10 min. The sterile outlet valve isthen opened again, and the suspension is concentrated as describedpreviously. After about 5469 g of clear filtrate has been discharged,the outlet valve is closed.

A further approx. 1956 g of precooled water for injections (11+/−3° C.)are then filtered sterile into the container while stirring (=suspension3). After the addition, suspension 3 is stirred for about 10 min. Thesterile outlet valve is then again opened, and the suspension isconcentrated as described previously. After about 4338 g of clearfiltrate has been discharged, the outlet valve is closed. Then 1560.1 gof a 7.4% (m/m) mannitol solution are filtered sterile into thecontainer while stirring (=suspension 4). The addition is followed bystirring for a further 10-15 min and then the final suspension 4 isdispensed through the suspension outlet valve (see FIG. 3, suspensionoutlet 7) into 10R glass vials. The solution for dispensing contains notmore than 10% ethanol. The molar ratio of cetrorelix to embonate is 2:1.The filled vials are placed in the lyophilizer, frozen at about −45° C.and lyophilized at a plate temperature increasing from −45° C. to +20°C. in vacuo in the primary drying and at about 25° C. in the secondarydrying. The freeze-drying system is then flushed with sterile nitrogen,the vials are closed with suitable stoppers in the system and thencrimp-capped. 2 ml of water for injections are used per vial toreconstitute the lyophilizate. The suspension obtained by gentleswirling can be administered s.c. or i.m.

Example 8 Production of a Steril Suspension of Cetrorelix Embonate (2:1)and of a Sterile Lyophilizate of 30 mg of Cetrorelix Embonate Using theSeparation Process by Means of Hollow Fiber Membrane Filter Separation

A suspension 1 of cetrorelix embonate is generated as in Example 1 in asuitable initial container (as component of a closed production systemas shown in FIG. 4). About 3540 g of the generated suspension 1 whichhas been precooled to a temperature of 11+/−3° C. are employed andpumped in a closed circulation with mixing through the production system(see FIG. 4) with hollow fiber membrane filter (UMP-153 Pall Microzamodule with PVDF hollow fiber membrane filter, nominal pore size: 0.2μm, Pall Corporation). The initial container is previously cooled to atemperature of 11+/−3° C. and maintained at this temperature throughoutthe process. Mixing is brought about by the pump/pump system and/or by astirrer which is optionally present in the initial container. Aseparation process in which the suspension of cetrorelix embonatecontinuously passes through the filter membrane is achieved, the clearfiltrate being separated on the latter (depletion). After an initialamount of 2122.7 g of filtrate has been separated, 1343.9 g of water forinjections which has been precooled to a temperature of 11+/−3° C. isput into the production system with mixing, and the separation processis continued. After a second amount of 1349.9 g of filtrate has beenseparated, 485.6 g of water for injections which has been precooled to atemperature of 11+/−3° C. is put into the initial container with mixing,and the continuous separation process is continued until a third amountof 1903.1 g of filtrate has been separated. The final suspension ofcetrorelix embonate is then mixed with sterile mannitol solution as inExample 1 and dispensed into 10R glass vials. The solution fordispensing contains not more than 10% ethanol. The molar ratio ofcetrorelix to embonate is 2:1. The filled vials are placed in thelyophilizer, frozen at about −45° C. and lyophilized at a platetemperature increasing from −45° C. to +20° C. in vacuo in the primarydrying and at about 25° C. in the secondary drying. The freeze-dryingsystem is then flushed with sterile nitrogen, the vials are closed withsuitable stoppers in the system and then crimp-capped. 2 ml of water forinjections are used per vial to reconstitute the lyophilizate. Thesuspension obtained by gentle swirling can be administered s.c. or i.m.

Example 9 Determination of the pH of Cetrorelix Base and Teverelix Base

The determination of the pH of a saturated solution of cetrorelix baseand teverelix base was carried out using a WTW pH meter level 1 pH meterfrom inoLab and an Idrolyte, pH 1-11; 0° C.-60° C., Order No. 6.0224.100electrode from Metrohm at room temperature (22° C.)

A total of 1.5 ml of water for injections was added in portions to 74.56mg of cetrorelix base in a vial while stirring until a cloudy, veryviscous solution was formed. The pH of this solution was measured atdifferent times over a period of up to 24 hours. The pH reached aplateau (pH=11.2) after about 25 min and was still there after 24 hours.The pH of the water for injections (blank) was 6.5.

A total of 0.75 ml of water for injections was added in portions to47.26 mg of teverelix base in a vial while stirring until a saturatedclear, very viscous solution was formed. The pH of this solution wasmeasured at various times over a period of up to 24 hours. The pHreached a plateau (pH=8.3) after about 30 min and was still there after24 hours. The pH of the water for injections (blank) was 6.5.

Example 10 Measurement of the Particle Size Distribution of theParticles of a Suspension of Cetrorelix Embonate (2:1)

The particle size distribution of the particles of a suspension ofcetrorelix embonate (2:1) was carried out by laser diffractrometry usinga Master Sizer X, a small volume unit MSX 1 and a “flow cell” fromMalvern Instruments and the following parameters: focus: 300 mm (range1.2-600 μm), polydisperse model, active beam length: 2.4 mm,obscuration: 10-20%, dispersion medium: water, stirring speed: 3250 rpm(level: 6.5).

From a cetrorelix embonate (2:1) suspension produced as in Example 1,before carrying out the separation process using a filter, sufficientsuspension was added in portions while stirring to 95 ml of water forinjections which was introduced into the MSX 1 stirred cell to result inan obscuration of 10-20%. Stirring was then continued for a further 1.5min before the measurement was carried out while stirring. FIG. 5 showsthe result of the measurement of the particle size distribution. Theunimodal distribution is proof of the absence of agglomeration of theparticles of the cetrorelix embonate peptide complex and the absence ofsediments which are not or are only partially resuspendable. On thebasis of the measured particle size distribution, a stainless steelgauze (nominal pore size: 5 μm) was used as filter for the separationprocess.

30 mg of a cetrorelix embonate (2:1) lyophilizate produced as in Example1 were reconstituted analogously in 2 ml of water for injections, asuspension was produced by gentle swirling for 3 min, and the particlesize distribution was measured analogously. The unimodal distributionproves the absence of agglomeration of the particles of the cetrorelixembonate peptide complex and complete resuspendability of thelyophilizate.

Example 11 Determination of the Stability of Various Cetrorelix EmbonateFormulations

The stability of the following different cetrorelix embonateformulations was investigated in relation to the timing of theirinhomogeneity, i.e. the occurrence of a visually recognizable two-phasemixture:

-   -   A) P85P002A (suspension according to the invention),    -   B) D-20762-PRT/a [cetrorelix embonate (1:1.6) microparticle        formulation according to DE 43 42 092],    -   C) D-20762-PRT/a [cetrorelix embonate (1:1.6) microparticle        formulation according to Felberbaum et al. (1998)].

The formulations were reconstituted as lyophilizates with in each case 2ml of water for injections—in the case of A) and B)—and 2 ml of SM1medium [176.5 mg of mannitol, 21.1 mg of polysorbate 80, 83.9 mg ofcarboxymethylcellulose sodium, 31.4-52.5 mg of sodium hydroxide (0.1Nsolution) and water for injections ad 4.3 g)]—in the case of C)—,swirled for about 1-2 min and then the stability was observed visuallyover a period of 15 minutes.

Table 1 represents the visual observed stabilities of the abovementionedcetrorelix embonate formulations at various times. TABLE 1 TimeFormulation A) Formulation B) Formulation C) 0 min completely immediatesuspension, homogeneous inhomogeneity, initial signs of suspension, notwo-phase mixture incipient visually inhomogeneity recognizableinhomogeneity 2 min completely two-phase two-phase mixture homogeneousmixture, becoming clearer, suspension, no formation of a sedimentvisually sediment formation not yet recognizable evident inhomogeneity 4min completely two-phase two-phase homogeneous mixture, mixture,suspension, no progressive indications of visually formation of asediment recognizable sediment formation inhomogeneity 6 min completelytwo completely two-phase homogeneous separated phases: mixture,suspension, no liquid phase and formation of a visually sedimentsediment recognizable inhomogeneity 8 min completely two completelytwo-phase homogeneous separated phases: mixture, suspension, no liquidphase and progressive visually sediment formation of a recognizablesediment inhomogeneity 10 min  completely two completely two-phasehomogeneous separated phases: mixture, suspension, no liquid phase andprogressive visually sediment formation of a recognizable sedimentinhomogeneity 12 min  completely two completely two-phase homogeneousseparated phases: mixture, suspension, no liquid phase and progressivevisually sediment formation of a recognizable sediment inhomogeneity 15min  completely two completely two completely homogeneous separatedphases: separated phases: suspension, no liquid phase and liquid phaseand visually sediment sediment recognizable inhomogeneity

It is clearly evident from Table 1 that the suspension A) according tothe invention is stable over the period considered and no inhomogeneityto give a two-phase mixture occurs. By contrast, with the microparticleformulations B) and C) there is immediate or very rapid inhomogeneity toform two-phase mixtures with distinct sediment formation.

Example 12 In Vitro Active Ingredient Release from Various CetrorelixEmbonate Formulations

The in vitro active ingredient release from various cetrorelix embonateformulations was carried out as follows. An ERWEKA DFZ60 flow cellsystem from Erweka was employed. The cell size was 22.6 mm in each case.The flow medium used was physiological Ringer's solution (8.6 g NaCl+0.3g KCl+0.25 g CaCl₂ in 1 l of water for injections), with a flow rate of0.3 ml/min. The temperature was 37° C. during the procedure. Glass beads(diameter: 0.4-0.6 mm) from Sartorius were used. The flow cells wereprepared in each case in layers from the bottom to the top as follows: aglass ball with a diameter of 5 mm, about 2 cm of absorbent cotton, aglass frit (diameter: 2.5 cm), a layer of about 6 g of glass beads, inwhich the respective reconstituted formulations were uniformlydistributed with a 2 ml disposable syringe with hypodermic needle(Ø0.90×40 mm), and an additional layer of 1-2 g of glass beads.

The following 30 mg cetrorelix embonate formulations were employed inindependent duplication determinations: (i) P85P002A (suspensionaccording to the invention), (ii) DJ5 [cetrorelix embonate (1:1.6)microparticle formulation according to DE 43 42 092 and Felberbaum etal. (1998)], (iii) 9612-002/05-g (suspension obtainable according to DE100 40 700). P85P002A and 9612-002/05-g were each reconstituted aslyophilizates with 2 ml of water for injection and swirled for 1-2 minbefore they were injected into the layer of glass beads. DJ5 wasresuspended in 2 ml of SM1 medium [176.5 mg of mannitol, 21.1 mg ofpolysorbate 80, 83.9 mg of carboxymethylcellulose sodium, 31.4-52.5 mgof sodium hydroxide (0.1N solution) and water for injections ad 4.3 g)]and likewise swirled for about 1-2 min before the injection. Fractionsof the flow medium which had flowed through the flow cell system werecollected over a period of 191 hours, and the amount of cetrorelixreleased in each case was determined by HPLC using an externalcetrorelix standard. The result of the HPLC determination is shown inFIG. 6 as the respective cumulative amount of active ingredient releasedover the entire period of 191 hours. The distinctly improved activeingredient release of the suspensions according to the invention isunambiguously evident.

Example 13 Comparison of the Testosterone Suppression in Male Persons

60 mg of a cetrorelix embonate (2:1) lyophilizate produced as in DE 10040 700, and 60 mg of a cetrorelix embonate (2:1) lyophilizate producedaccording to the invention were each reconstituted in 4 ml of water forinjections and administered parenterally as i.m. dose to men. Thecetrorelix plasma concentrations reached, and the testosteronesuppressions, were determined for both formulations after in each case 1week and 2 weeks compared with the initial level at the time ofadministration (week 0) (study 3107: suspension produced andadministered according to DE 100 40 700; study JAP: suspension producedand administered according to the invention).

FIG. 7 shows the determined testosterone suppression, which has beendepicted normalized (initial levels in each case at the time ofadministration (week 0)=100%).

The more advantageous hormone suppression of the suspension producedaccording to the invention is evident from FIG. 7. Thus, the suspensionaccording to the invention brings about marked hormone suppression bothafter one and after two weeks.

The above written description of the invention provides a manner andprocess of making and using it such that any person skilled in this artis enabled to make and use the same, this enablement being provided inparticular for the subject matter of the appended claims, which make upa part of the original description.

As used above, the phrases “selected from the group consisting of,”“chosen from,” and the like include mixtures of the specified materials.Terms such as “contain(s)” and the like as used herein are open termsmeaning ‘including at least’ unless otherwise specifically noted.

All references, patents, applications, tests, standards, documents,publications, brochures, texts, articles, etc. mentioned herein areincorporated herein by reference. Where a numerical limit or range isstated, the endpoints are included. Also, all values and subrangeswithin a numerical limit or range are specifically included as ifexplicitly written out.

The above description is presented to enable a person skilled in the artto make and use the invention, and is provided in the context of aparticular application and its requirements. Various modifications tothe preferred embodiments will be readily apparent to those skilled inthe art, and the generic principles defined herein may be applied toother embodiments and applications without departing from the spirit andscope of the invention. Thus, this invention is not intended to belimited to the embodiments shown, but is to be accorded the widest scopeconsistent with the principles and features disclosed herein.

1. A process for producing a sterile suspension of at least one slightlysoluble basic peptide complex, which comprises, under asepticconditions, a) i) mixing a sterile solution comprising at least one of asalt or a complex of a basic peptide and of an aliphatic or aromaticorganic carboxylic acid and/or salts thereof in a solvent or solventmixture, optionally with the addition of solubility-increasing and/oragglomeration-suppressing additives, or ii) combining and mixing asterile solution of a salt or complex of at least one basic peptide in asolvent or solvent mixture and a sterile solution of an aliphatic oraromatic organic carboxylic acid and/or salts thereof in a solvent orsolvent mixture, optionally with the addition of solubility-increasingand/or agglomeration-suppressing additives, b) generating, by mixing andaddition of a diluent or diluent mixture in one or more steps, asuspension of a slightly soluble basic peptide complex of the basicpeptide with the carboxylic acid, which complex precipitates at thelatest after addition of the diluent or diluent mixture, c) depleting,while mixing in a continuous or stepwise separation process, the solventor solvent mixture, free non-peptide ions, excess carboxylic acid andoptionally added solubility-increasing and/or agglomeration-suppressingadditives in the resulting suspension, with the liquid content of thesuspension being reduced and optionally further diluent or diluentmixture being added in one or more steps, and d) optionally adding tothe slightly soluble basic peptide complex, while mixing the sterilesuspension during c) and/or thereafter, one or more pharmaceuticalexcipients, carriers and/or bulking agents.
 2. The process as claimed inclaim 1, comprising a) ii), wherein the sterile solution of the salt orcomplex of the basic peptide and the sterile solution of the aliphaticor aromatic organic carboxylic acid and/or salts thereof are present inthe same solvent or solvent mixture in step a) ii).
 3. The process asclaimed in claim 1, wherein a sterile solution comprising a salt orcomplex of a basic peptide and an aliphatic or aromatic organiccarboxylic acid and/or salts thereof in a solvent or solvent mixture ismixed in step a), optionally with the addition of solubility-increasingand/or agglomeration-suppressing additives.
 4. The process as claimed inclaim 3, wherein the sterile solution for step a) is prepared by a′)dissolving a salt or complex of a basic peptide in a solvent or solventmixture, b′) adding the aliphatic or aromatic organic carboxylic acidand/or salts thereof in solid, suspended or dissolved form with mixingto the solution of the salt or complex of the basic peptide from stepa), and dissolving, and c′) sterilizing the solution obtained in thisway by filtration.
 5. The process as claimed in claim 1, wherein furtherdiluent or diluent mixture is added in one or more steps with mixing inthe separation process in step c).
 6. The process as claimed in claim 1,wherein the same diluent or diluent mixture is employed in step b) andin step c).
 7. A process for producing sterile lyophilizates of slightlysoluble basic peptide complexes, which comprises lyophilizing thesterile suspension of the slightly soluble basic peptide complexobtained in steps c) or d) of the process as claimed in claim 1 andoptionally adding to the lyophilizate obtained one or morepharmaceutical excipients, carriers and/or bulking agents.
 8. A processfor producing sterile suspensions suitable for parenteral administrationof slightly soluble basic peptide complexes, which comprisesreconstituting the lyophilizate obtained by the process as claimed inclaim 7 with a sterile physiologically tolerated reconstituting medium.9. The process as claimed in claim 1, wherein the basic peptide isselected from the group consisting of: the LHRH superagonists goserelin,leuprorelin, triptorelin and the LHRH antagonists abarelix, antide,azaline B, A-75998, cetrorelix, degarelix, detirelix, ozarelix(D-63153), ganirelix, Nal-Glu antagonist, remorelix, RS-68439, teverelixand the LHRH antagonists according to the compounds: of the generalformula (I)

in which n is the number 3 or 4, R1 is an alkyl group, an alkoxy group,an aryl group, a heteroaryl group, an aralkyl group, a heteroaralkylgroup, an aralkyloxy group or a heteroaralkyloxy group, in each caseunsubstituted or substituted, R2 and R3 are independently of one anothereach a hydrogen atom, an alkyl group, an aralkyl group or aheteroaralkyl group, in each case unsubstituted or substituted, wherethe substitution in turn may consist of an aryl group or heteroarylgroup, or —NR²R³ is an amino acid group, and R4 is a group having theformula (II)

in which p is an integer from 1 to 4, R5 is hydrogen or an alkyl groupand R6 is an unsubstituted or substituted aryl group or heteroarylgroup, or R4 is a ring of the general formula (III)

in which q is the number 1 or 2, R7 is a hydrogen atom or an alkylgroup, R8 is a hydrogen atom or an alkyl group and X is an oxygen orsulfur atom, where the aromatic or heteroaromatic radicals may be partlyor completely hydrogenated and chiral carbon atoms may have the R or Sconfiguration, the LHRH antagonists according to the compounds of thegeneral formula (IV)Ac-D-Nal(2)-D-(pCl)Phe-D-Pal(3)-Ser-Tyr-D-Xxx-Leu-Arg-Pro-D-Ala-NH₂  (IV)in which D-Xxx is an amino acid group of the general formula (V)

in which n is the number 3 or 4, R4 is a group having the formula (VI)

in which p is an integer from 1 to 4, R5 is hydrogen or an alkyl groupand R6 is an unsubstituted or substituted aryl group or heteroarylgroup, or R4 is a ring of the general formula (VII)

in which q is the number 1 or 2, R7 is a hydrogen atom or an alkylgroup, R8 is a hydrogen atom or an alkyl group and X is an oxygen orsulfur atom, and the LHRH antagonists according to the compounds of thefollowing general formula (VIII)A-Xxx¹-Xxx²-Xxx³-Xxx⁴-Xxx⁵-Xxx⁶-Xxx⁷-Xxx⁸-Xxx⁹-Xxx¹⁰-NH₂  (VIII) inwhich A is an acetyl or a 3-(4-fluorophenyl)propionyl group, Xxx¹ isD-Nal(1) or D-Nal(2), Xxx²-Xxx³ is D-Cpa-D-Pal(3) or a single bond, Xxx⁴is Ser, Xxx⁵ is N-Me-Tyr, Xxx⁶ is D-Cit, D-Hci or a D-amino acid groupof the general formula (IX)

in which n is the number 3 or 4, where R1 is a group having the generalformula (X)—(CH₂)_(p)—CO—NR2R3  (X) in which p is an integer from 1 to 4, R2 ishydrogen or an alkyl group and R3 is an unsubstituted or substitutedaryl group or heteroaryl group, and R1 is a3-amino-1,2,4-triazole-5-carbonyl group or R1 is a ring of the generalformula (XI)

in which q is the number 1 or 2, R4 is a hydrogen atom or an alkylgroup, R5 is a hydrogen atom or an alkyl group and X is an oxygen orsulfur atom, Xxx⁷ is Leu or Nle, Xxx⁸ is Arg or Lys(IPr), Xxx⁹ is Proand Xxx¹⁰ is Ala or Sar.
 10. The process as claimed in claim 1, whereinthe basic peptide is at least one LHRH antagonist selected from thegroup consisting of cetrorelix, ozarelix (D-63153) and teverelix. 11.The process as claimed in claim 1, wherein the aliphatic or aromaticorganic carboxylic acid is at least one selected from the groupconsisting of: adipic acid, alginic acid, malic acid, ascorbic acid,benzene-sulfonic acid, succinic acid, dibutyl phosphoric acid,dihexadecyl phosphoric acid, dioctyl phosphoric acid, acetic acid,fumaric acid, gluconic acid, glucuronic acid, glutamic acid,alpha-lipoic acid, maleic acid, malonic acid, lactic acid, octylphosphoric acid, oleic acid, tartaric acid, embonic acid, citric acid,palmitic acid, salicylic acid, tannic acid, stearic acid, benzoic acid,and cinnamic acid.
 12. The process as claimed in claim 1, wherein thealiphatic or aromatic organic carboxylic acid is at least one selectedfrom the group consisting of embonic acid, citric acid, and palmiticacid.
 13. The process as claimed in claim 1, wherein at least one ofwater, ethanol, acetic acid, methanol, propanol, isopropanol, n-butanol,tert-butanol, acetone or methyl ethyl ketone is employed as solvent. 14.The process as claimed in claim 13, wherein a water-ethanol mixturehaving an ethanol content of from 10 to 99% (m/m) is employed as solventmixture.
 15. The process as claimed in claim 1, wherein at least one ofwater, ethanol, acetic acid, methanol, propanol, isopropanol, n-butanol,tert-butanol, acetone and methyl ethyl ketone is employed as diluent ordiluent mixture.
 16. The process as claimed in claim 15, wherein wateris employed as diluent.
 17. The process as claimed in claim 1, whereinthe salt employed in step a) or the complex of the basic peptide is atleast one salt or complex selected from the group consisting of acetate,hydrochloride, chloride, fluoride, bromide, iodide, gluconate,glucuronate, trifluoroacetate, glutamate, lactate, phosphate, hydrogenphosphate, dihydrogen phosphate, aspartate, succinate, and tartrate. 18.The process as claimed in claim 1, wherein the molar ratio of basicpeptide to carboxylic acid in the slightly soluble basic peptide complexis 20:1-1:20.
 19. The process as claimed in claim 1, wherein noadditives which increase the solubility and/or suppress agglomerationare added in step a) of the process.
 20. The process as claimed in claim1, wherein process steps a) to d) are carried out in one and the samecontainer, it being possible for the container optionally to have aremovable device for mixing.
 21. The process as claimed in claim 1,wherein process steps a) to d) are carried out in two or morecontainers, it being possible for each container optionally to have aremovable device for mixing, and it also being possible for two or moreof the process steps to be carried out in one container.
 22. The processas claimed in claim 1, wherein the depletion in the separation processin step c) takes place by use of a filter on the basis of the screensize and/or of the retention range of the filter.
 23. The process asclaimed in claim 22, wherein a stainless steel gauze with a retentionrange of 1-250 μm is employed as filter.
 24. The process as claimed inclaim 22, wherein the filter is one or more hollow fiber membranes madeof one or more materials selected from the group consisting of:polyamide, polycarbonate, polypropylene, PTFE, PVDF, polysulfone and hasa screen size and/or retention range of 0.1-250 μm.
 25. The process asclaimed in clai 22, wherein the depletion takes place with applicationof pressure.
 26. The process as claimed in claim 22, wherein the mixingin the separation process in step c) is brought about by a stirrerdisposed above the filter and is optionally removable.
 27. The processas claimed in claim 22, wherein the mixing in the separation processafter step c) is brought about by pumps and optionally additionally byan optionally removable mixer.
 28. The process as claimed in claim 1,wherein the depletion in the separation process in step c) takes placeby centrifugation, it being possible for the centrifugation to becarried out in one or more steps.
 29. The process as claimed in claim 1,wherein one or more pharmaceutical excipients, carriers and/or bulkingagents selected from the group consisting of mannitol, sorbitol,xylitol, trehalose, glucose, soluble starch, sucrose and saccharose areadded to the suspension or the lyophilizate.
 30. The process as claimedin claim 1, which comprises a) mixing a sterile solution comprising theacetate salt of at least one LHRH antagonist selected from the groupconsisting of cetrorelix, teverelix, and ozarelix (D-63153) and the saltof at least one carboxylic acid selected from the group consisting ofembonic acid, citric acid, and palmitic acid in an aqueous ethanolicsolvent mixture having an ethanol content of from 50 to 90% (m/m), b)generating, by mixing and addition of water as diluent in one or moresteps, a suspension of the slightly soluble basic peptide complex of thebasic peptide with the carboxylic acid, where the molar ratio of basicpeptide to carboxylic acid in the slightly soluble basic peptide complexassumes a value of between 2:1 and 1:2, c) depleting, while mixing andwith further addition of water as further diluent in one or more stepsand optionally with application of pressure, ethanol, free non-peptideions and excess carboxylic acid in the suspension obtained in step b)through use of a stainless steel gauze filter having a retention rangeof 2-100 μm and reducing the liquid content of the suspension, and d)adding, while mixing, to the sterile suspension of the slightly solublebasic peptide complex in c), mannitol, where process steps a) to d) arecarried out in one and the same or two containers.
 31. The process asclaimed in claim 30, which comprises employing as filter in step c) oneor more hollow fiber membranes which preferably consist of PVDF and/orpolysulfone and have a screen size and/or retention range of 0.1-100 μm,the mixing being brought about by pumps and optionally additionally byan optionally removable mixer.
 32. A process for producing sterilelyophilizates of slightly soluble basic peptide complexes, whichcomprises lyophilizing the sterile suspension obtained in step d) of theprocess as claimed in claim
 30. 33. A process for producing sterilesuspensions, suitable for parenteral administration, of slightly solublebasic peptide complexes, which comprises reconstituting the lyophilizateobtained by the process as claimed in claim 32 with water for injection.34. A sterile suspension of a slightly soluble basic peptide complexobtained by the process as claimed in claim
 1. 35. A sterilelyophilizate of a slightly soluble basic peptide complex obtained by theprocess as claimed in claim
 7. 36. A pharmaceutical formulation forparenteral administration, comprising at least one sterile suspension ofa slightly soluble basic peptide complex as claimed in claim
 34. 37. Amethod for the treatment of benign or malignant neoplastic diseases,male fertility control, hormone therapy, hormone-dependent neoplasticdiseases, female sub- or infertility, in vitro fertilization, femalecontraception, HIV infections, neurological or neurodegenerativedisorders and/or for protection against side effects due tochemotherapy, comprising administering to a patient in need thereof asterile suspension of a slightly soluble basic peptide complex obtainedby the process as claimed in claim 1, a lypholizate thereof, or areconstituted lypholizate thereof.
 38. A method for the treatment ofprostate cancer, benign prostate hyperplasia (BPH), endometriosis,uterine fibroids, uterine myomas, breast cancer, premenopausal breastcancer, uterine cancer, endometrial cancer, cervical cancer, ovariancancer, precocions puberty, hirsutism, polycystic ovary syndrome, AIDS,ARC, Karposi sarcomas, tumors originating from the brain and/or nervoussystem and/or meninges, dementia and/or Alzheimer's comprisingadministering to a patient in need thereof a sterile suspension of aslightly soluble basic peptide complex obtained by the process asclaimed in claim 1, a lypholizate thereof, or a reconstitutedlypholizate thereof.
 39. A pharmaceutical composition comprising: anaseptic reaction product of: a sterile solution of a cetrorelix salt andan organic carboxylic acid or salt in at least one solvent with at leastone sterile diluent, wherein the reaction product is depleted ofsolvent, of free salt ions and of free carboxylic acid.
 40. Apharmaceutical composition comprising a slightly soluble cetrorelix saltor complex, wherein the cetrorelix salt is free of any tracers of ionexchange resin or of any materials embedded therein, and substantiallyfree of solvent, free non-peptide ions, and/or excess carboxylic acid.41. The composition of claim 40, wherein greater than 50% of particlesof the cetrorelix salt have a particle diameter less than 20 μm.
 42. Thecomposition of claim 41, wherein greater than 90% of the particles havea particle diameter of less than 100 μm.
 43. A slightly solublecetrorelix salt composition comprising about 30 mg cetrorelix salt,wherein the composition cumulatively releases greater than 15 mg of theCetrorelix salt in vitro over 160 hours.
 44. A method of asepticallymanufacturing a cetrorelix salt comprising: mixing a) a sterile solutioncomprising: 1) the cetrorelix salt in at least one solvent; 2) anorganic carboxylic acid or salt; and b) at least one diluent.
 45. Amethod of aseptically manufacturing a cetrorelix salt comprising: mixinga) a sterile solution of a cetrorelix salt in at least one firstsolvent; and b) a sterile solution of an organic carboxylic acid or saltin at least one second; to form a third solution; and c) mixing thethird solution with a diluent.
 46. A method of aseptically manufacturingcetrorelix pamoate comprising: a) dissolving cetrorelix acetate in waterto form a first solution; b) mixing ethanol into the solution to form anethanol/water solution that is predominantly ethanol; c) adding, whilestirring, disodium embonate to the ethanol/water solution to form acetrorelix embonate solution; d) sterilizing the cetrorelix embonatesolution by filtration; e) continuously adding sterile water into thecetrorelix embonate solution while stirring, to form a suspension ofcetrorelix embonate particles; f) continuously removing liquid from thesuspension using filtration to form a concentrated suspension ofcetrorelix embonate particles; g) adding, while stirring, a sterilemannitol solution into the concentrated suspension; and h) lyophilizingthe concentrated suspension.
 47. An aseptic, cetrorelix pamoatemanufacturing apparatus comprising: at least one container comprising: acetrorelix pamoate suspension forming chamber and a permeate chamber; afilter filterably separating the cetrorelix pamoate suspension formingchamber and the permeate chambers; a stirrer placed within thecetrorelix pamoate suspension forming chamber chamber adjacent to thefilter.
 48. An aseptic cetrorelix pamoate manufacturing apparatuscomprising: at least one container comprising: a filter positioned in abottom portion of the container having a pore size sufficient tosubstantially retain particles of cetrorelix pamoate, while passing aliquid content of a suspension containing said particles of cetrorelixpamoate; and a mixer positioned adjacent to the filter that, whenmixing, maintains the retained particles in suspension.